I've installed lineage OS and didn't like it, then I downloaded the pixel experience ROM to try it out.
So i went into TWRP, wiped everything, internal storage, cache, dalvik, system, etc. and then flashed the pixel experience ROM, and now it is stuck in the fastboot mode..
It will not boot into the normal OS! And now i've wiped everything again, and then powered off the phone
What should I do? I'm feel panicked now..please help
guyzz6370 said:
I've installed lineage OS and didn't like it, then I downloaded the pixel experience ROM to try it out.
So i went into TWRP, wiped everything, internal storage, cache, dalvik, system, etc. and then flashed the pixel experience ROM, and now it is stuck in the fastboot mode..
It will not boot into the normal OS! And now i've wiped everything again, and then powered off the phone
What should I do? I'm feel panicked now..please help
Click to expand...
Click to collapse
Download AIT Here : https://forum.xda-developers.com/mi-8/development/tool-tool-one-driverstwrpfactory-t3895807
Use it to reinstall TWRP and unencrypted userdata ( only if needed) Then reinstall whatever Rom, Gapps ( if needed) and Root.
You likely missed a step or flashed something such as gapps on the Pixel Rom, and that caused this issue. FYI, as long as you have fastboot there is never a need to worry. Once this is sorted out I would highly recommend that you make a TWRP backup and save it to your PC, to resolve any deeper issues such as sensor problems.
tsongming said:
Download AIT Here : https://forum.xda-developers.com/mi-8/development/tool-tool-one-driverstwrpfactory-t3895807
Use it to reinstall TWRP and unencrypted userdata ( only if needed) Then reinstall whatever Rom, Gapps ( if needed) and Root.
You likely missed a step or flashed something such as gapps on the Pixel Rom, and that caused this issue. FYI, as long as you have fastboot there is never a need to worry. Once this is sorted out I would highly recommend that you make a TWRP backup and save it to your PC, to resolve any deeper issues such as sensor problems.
Click to expand...
Click to collapse
Ok, it happens like this. First I had MIUI, then I installed LOS (which is working) but I didn't like it, so I went and downloaded the PE ROM, and then I just went into TWRP, deleted everything, wipe everything, etc and then I transferred the PE zip file to my phone's internal storage via usb and then I flash it using TWRP. I then went to reboot system, and now it is stuck in the fastboot.
flashed something such as gapps on the Pixel Rom, and that caused this issue
Click to expand...
Click to collapse
I really didn't flash gapps on the PE ROM, because I read that PE had gapps pre-installed, this is something I'm sure I didn't do.
FYI, as long as you have fastboot there is never a need to worry
Click to expand...
Click to collapse
Really thanks for telling me this, I feel relieved already! :laugh:
deeper issues such as sensor problems.
Click to expand...
Click to collapse
really? sensor problems? omg
Use it to reinstall TWRP and unencrypted userdata ( only if needed) Then reinstall whatever Rom, Gapps ( if needed) and Root.
Click to expand...
Click to collapse
okok, how do I use it? which options to click on?
FIXED! Ok, I fixed by downloading the MIUI fastboot ROM located here >> http://en.miui.com/a-234.html
When you download the ROM, you need to extract it, because it comes downloaded as a .tgz, when you extract it becomes a .tar, then you need to extract AGAIN to have the final normal folder, inside this folder you will find all the needed .bat files.
Then you need the Mi flash tool >> api.en.miui.com/url/MiFlashTool
After you download the Mi flash tool, you need to connect your phone via usb and go into fastboot (volume up + power button), then inside the Mi flash tool you need to click on refresh to detect your device.
Once you see your device, you need to go to your final extracted folder and then copy the path of the folder (the location of the folder), by right-clicking the path and click on copy.
You now paste the path onto the mi flash tool, and then click on flash!
When it finishes flashing, it will reboot, but this time into the system! :laugh::laugh::laugh::laugh::laugh:
omg, I'm so happy this is fixed, i thought my mi 8 was gone forever!
Hopefully someone will find this useful in the future!
guyzz6370 said:
FIXED! Ok, I fixed by downloading the MIUI fastboot ROM located here >> http://en.miui.com/a-234.html
When you download the ROM, you need to extract it, because it comes downloaded as a .tgz, when you extract it becomes a .tar, then you need to extract AGAIN to have the final normal folder, inside this folder you will find all the needed .bat files.
Then you need the Mi flash tool >> api.en.miui.com/url/MiFlashTool
After you download the Mi flash tool, you need to connect your phone via usb and go into fastboot (volume up + power button), then inside the Mi flash tool you need to click on refresh to detect your device.
Once you see your device, you need to go to your final extracted folder and then copy the path of the folder (the location of the folder), by right-clicking the path and click on copy.
You now paste the path onto the mi flash tool, and then click on flash!
When it finishes flashing, it will reboot, but this time into the system! :laugh::laugh::laugh::laugh::laugh:
omg, I'm so happy this is fixed, i thought my mi 8 was gone forever!
Hopefully someone will find this useful in the future!
Click to expand...
Click to collapse
Glad you fixed it but you didn't really need to use the flashbat method for this issue. although yes it works.
I have written these exact instructions in the questions and answers section numerous times. You should still download and install AIT, in case you ever need it in the future. Plus, it has other great features such as keeping fastboot tools up to date, systemwide ADB use, as well as the many, many other features.
To help you understand what happened
Somehow, your data became encrypted, badly enough that you could not access your data, system or recovery. This issue has happened to alot of people including myself...many times.
So when I was talking about using AIT to remove encryption, what that basically means is the AIT tool formats the userdata/user storage. After that is resolved, you can, reinstall TWRP, and be back to being able to use custom roms again.
Now that you are restored,
Boot to TWRP and make a complete backup up of your installation, checking everybox.
Next connect to your PC and copy the backup from storage/Twrp/Backups, over to your PC.
Never delete this backup. If you have an issue in the future, such as Wifi, BT, or cellular not connecting, or if you have a Wifi mac address of 02:00:00:00:00 you can use the Recovery to restore your partitions, notably the persist partition.
Restoring your backup will fully resolve those kinds of issues, even when flashbat will not.
Enjoy
This issue has happened to alot of people including myself...many times.
Click to expand...
Click to collapse
I'm interested to read about this too, can you link me to some threads of other people having the same issue?
Now that you are restored,
Boot to TWRP and make a complete backup up of your installation, checking everybox.
Next connect to your PC and copy the backup from storage/Twrp/Backups, over to your PC.
Never delete this backup. If you have an issue in the future, such as Wifi, BT, or cellular not connecting, or if you have a Wifi mac address of 02:00:00:00:00 you can use the Recovery to restore your partitions, notably the persist partition.
Click to expand...
Click to collapse
Yeah, time to make a backup! A working one!
guyzz6370 said:
I'm interested to read about this too, can you link me to some threads of other people having the same issue?
Yeah, time to make a backup! A working one!
Click to expand...
Click to collapse
Sure this post has an issue that I also ended up having myself :
https://forum.xda-developers.com/mi-8/help/xiaomi-mi-8-wifi-issue-help-t3941288
Read through the post, everything that I recommended usually works ...most of the time. However, I recently had the exact issue where nothing worked including using Fastboot FlashAll.bat , and I tried several versions of stock and kept having persist issues, which caused my Wifi and mobile to not work. Note, the solution here is using your backup ( Using someone else's, apparently does not always work)
What finally resolved my issue was restoring my own recovery backups which fortunately I had previously made one with the Xiaomi EU version of the backup and it finally solved the issue.
For the record, booting the phone into EDL mode and using the QPST program to restore the factory rom should also work. Plus, QPST has a built in tool that is specific to repairing the Radio, IMEI, Mac Address Etc. Needless to say, restoring your TWRP backup is much much easier and much less stressful than doing trial and error with QPST.
See the screenshots ( attached) One backup made with official TWRP makes a highly compressed version of the backup. I would also suggest making a backup of with the linked version of TWRP from the Xiaomi.EU website, this version decompresses some of the driver images allow you to restore individual files such as individual persist images
TWRP-3.3.1-0607-XIAOMI8-CN-wzsx150 .zip ( Two Languages, Chinese and English)
https://mega.nz/#!QstBnAaD!V6riZpEjctWhzWhoFcDDEv0wRlFESfcEsxAHpdaerxE
tsongming said:
Sure this post has an issue that I also ended up having myself :
https://forum.xda-developers.com/mi-8/help/xiaomi-mi-8-wifi-issue-help-t3941288
Read through the post, everything that I recommended usually works ...most of the time. However, I recently had the exact issue where nothing worked including using Fastboot FlashAll.bat , and I tried several versions of stock and kept having persist issues, which caused my Wifi and mobile to not work. Note, the solution here is using your backup ( Using someone else's, apparently does not always work)
What finally resolved my issue was restoring my own recovery backups which fortunately I had previously made one with the Xiaomi EU version of the backup and it finally solved the issue.
For the record, booting the phone into EDL mode and using the QPST program to restore the factory rom should also work. Plus, QPST has a built in tool that is specific to repairing the Radio, IMEI, Mac Address Etc. Needless to say, restoring your TWRP backup is much much easier and much less stressful than doing trial and error with QPST.
See the screenshots ( attached) One backup made with official TWRP makes a highly compressed version of the backup. I would also suggest making a backup of with the linked version of TWRP from the Xiaomi.EU website, this version decompresses some of the driver images allow you to restore individual files such as individual persist images
TWRP-3.3.1-0607-XIAOMI8-CN-wzsx150 .zip ( Two Languages, Chinese and English)
https://mega.nz/#!QstBnAaD!V6riZpEjctWhzWhoFcDDEv0wRlFESfcEsxAHpdaerxE
Click to expand...
Click to collapse
Well well, it seems that there are some scary stuff that can happen to your device that thank God I personally don't have to deal with :laugh:
I was already scared sh**less when I started this post, and luckily for me my device is fine now running the PE ROM (so smooth and beautiful) and never encountered any radio/sensor issues..
So from what I can gather...always make a TWRP back up of your device so if anything stupid happens in the future (I think it's unlikely, but just to be safe...) you can easily restore and your device is safe again..so yeah thank God I don't have to deal with more complex issues :fingers-crossed:
And thanks for answering, it very comforting to know that there are people like you who answer on these forums whenever urgent help is needed...so thanks for that!:good::good:
guyzz6370 said:
Well well, it seems that there are some scary stuff that can happen to your device that thank God I personally don't have to deal with :laugh:
I was already scared sh**less when I started this post, and luckily for me my device is fine now running the PE ROM (so smooth and beautiful) and never encountered any radio/sensor issues..
So from what I can gather...always make a TWRP back up of your device so if anything stupid happens in the future (I think it's unlikely, but just to be safe...) you can easily restore and your device is safe again..so yeah thank God I don't have to deal with more complex issues :fingers-crossed:
And thanks for answering, it very comforting to know that there are people like you who answer on these forums whenever urgent help is needed...so thanks for that!:good::good:
Click to expand...
Click to collapse
Yes, exactly and although its somewhat rare it happened to me for no real reason, suddenly the phone froze and would not boot again. To be fair I was trying out an untested version of TWRP. However I was not experiencing any issues for weeks, until I installed Swift themer, similar to Substratum. Though I am not sure that it was related to the issue.
Bottom line, make the TWRP backup ASAP, it will literally take you no more than 15 minutes to make it and back it up to your PC. This way you never ever have to worry about unpredictable issues., pass it on to any friends or relatives to do the same.
Enjoy your awesome phone, Cheers.
tsongming said:
Yes, exactly and although its somewhat rare it happened to me for no real reason, suddenly the phone froze and would not boot again. To be fair I was trying out an untested version of TWRP. However I was not experiencing any issues for weeks, until I installed Swift themer, similar to Substratum. Though I am not sure that it was related to the issue.
Bottom line, make the TWRP backup ASAP, it will literally take you no more than 15 minutes to make it and back it up to your PC. This way you never ever have to worry about unpredictable issues., pass it on to any friends or relatives to do the same.
Enjoy your awesome phone, Cheers.
Click to expand...
Click to collapse
So I tried restoring from the backup and...wasn't what I expected..I expected it to be 100% exact. I thought it will be as if I restarted my phone and when I turn on the phone again, it will be like nothing ever happened..
but the restore feature isn't perfect
Firstly, when I checked all the partitions to restore, it gave me the 255 error..so what ended up working for me was to uncheck the recovery,cache, and data partitions..this restored the device and the device booted (it wasn't booting before this, it will show the mi logo and shut off).
After booting up, I still needed to set up my phone..
But other than that...it does seem to save some of phone's settings
certain settings, wallpapers, status bar icons, home screen icons..these things seem to have been saved..but everything else is still starting from fresh..
What gives? I thought it was supposed to behave as if I restarted my phone and nothing happened...
guyzz6370 said:
So I tried restoring from the backup and...wasn't what I expected..I expected it to be 100% exact. I thought it will be as if I restarted my phone and when I turn on the phone again, it will be like nothing ever happened..
but the restore feature isn't perfect
Firstly, when I checked all the partitions to restore, it gave me the 255 error..so what ended up working for me was to uncheck the recovery,cache, and data partitions..this restored the device and the device booted (it wasn't booting before this, it will show the mi logo and shut off).
After booting up, I still needed to set up my phone..
But other than that...it does seem to save some of phone's settings
certain settings, wallpapers, status bar icons, home screen icons..these things seem to have been saved..but everything else is still starting from fresh..
What gives? I thought it was supposed to behave as if I restarted my phone and nothing happened...
Click to expand...
Click to collapse
What? It seems that you missed the point of what I was suggesting.
Why would you assume that the restore would restore everything and it would be like nothing happened, where did I say that? Restoring the back would definitely be like nothing happened to your missing partitions.
I never said anything about fully restoring your phone although that is indeed completely possible if done right, and you restore the system base and files in storage that were present when you made the backup.
The only thing that I was talking about is when/ if you eventually experience a unsolvable persist issue. If you flash a lot of different roms, frequently it is a problem that you may eventually experience for yourself. Google Xiaomi persist issue. A lot of people had that issue about a month ago.
So again, the point is to have a quick fix on hand, that you can restore, drivers and crucial partitions without having to use EDL mode.
The full backup does not include your files, or settings and that message appears within TWRP when you make the back up.
Some devices including Xiaomi have "special partitions" like WiMAX, pds, efs, etc. These partitions almost never need to be included in a normal backup. However, it's usually a good idea to make a single backup of these partitions and hang on to them just in case.
tsongming said:
What? It seems that you missed the point of what I was suggesting.
Why would you assume that the restore would restore everything and it would be like nothing happened, where did I say that? Restoring the back would definitely be like nothing happened to your missing partitions.
I never said anything about fully restoring your phone although that is indeed completely possible if done right, and you restore the system base and files in storage that were present when you made the backup.
The only thing that I was talking about is when/ if you eventually experience a unsolvable persist issue. If you flash a lot of different roms, frequently it is a problem that you may eventually experience for yourself. Google Xiaomi persist issue. A lot of people had that issue about a month ago.
So again, the point is to have a quick fix on hand, that you can restore, drivers and crucial partitions without having to use EDL mode.
The full backup does not include your files, or settings and that message appears within TWRP when you make the back up.
Some devices including Xiaomi have "special partitions" like WiMAX, pds, efs, etc. These partitions almost never need to be included in a normal backup. However, it's usually a good idea to make a single backup of these partitions and hang on to them just in case.
Click to expand...
Click to collapse
oh.. because i thought it would be perfect like nothing happened ? that's the whole point of backing up right?
I expected to be like a normal hard disk on your computer..on a hard disk i can just make a clone of the disk and clone it to a new hard disk, and the computer starts like nothing happened...
so i assumed it was the same for a phone too, but apparently not ?
guyzz6370 said:
oh.. because i thought it would be perfect like nothing happened ? that's the whole point of backing up right?
I expected to be like a normal hard disk on your computer..on a hard disk i can just make a clone of the disk and clone it to a new hard disk, and the computer starts like nothing happened...
so i assumed it was the same for a phone too, but apparently not ?
Click to expand...
Click to collapse
Miui local backup works something like that. Titanium backup used to be awesome for that kind of restore, but on pie roms it's kind of buggy
If using an Aosp rom, there is a program called migrate that can restore apps but the user data part hasn't always worked for me.
TWRP full restore, along with manually restoring storage media from the desktop will be close to using a restore point from a PC or restoring a time machine backup on a mac but still not the same.
Now you have the backup so your phone is safe from weird future issues. If that ever happen message me and I will help you .
Sent from my Xiaomi MI 8 using XDA Labs
My device is stuck in the initial boot sequence in which the logo will show as if it is booting normally, then it will stay on this screen until it goes completely blank, at which point I have to hold the power button for a long period of time to get it back to the boot sequence. My phone is unlocked and I was trying my first time at flashing a custom recovery and OS, I flashed my device with TWRP and successfully installed it along with a flash of pixel experience, After using pixel experience I wanted to try lineage OS since it wasn't as good as I hoped, so I tried to get into the TWRP and I could not do it at all I tried every method I could search. After an hour of trying different methods of getting to twrp I tried to re-flash the recovery and that is when the phone because unresponsive and does what I have described above. I currently have access to fast boot and I dont want to go ****ing my phone up more than I have. If anyone can give me a step by step guide on how to fix this it would help so much since im new to android and I cant afford another £400 phone.
Thanks
BJack0 said:
My device is stuck in the initial boot sequence in which the logo will show as if it is booting normally, then it will stay on this screen until it goes completely blank, at which point I have to hold the power button for a long period of time to get it back to the boot sequence. My phone is unlocked and I was trying my first time at flashing a custom recovery and OS, I flashed my device with TWRP and successfully installed it along with a flash of pixel experience, After using pixel experience I wanted to try lineage OS since it wasn't as good as I hoped, so I tried to get into the TWRP and I could not do it at all I tried every method I could search. After an hour of trying different methods of getting to twrp I tried to re-flash the recovery and that is when the phone because unresponsive and does what I have described above. I currently have access to fast boot and I dont want to go ****ing my phone up more than I have. If anyone can give me a step by step guide on how to fix this it would help so much since im new to android and I cant afford another £400 phone.
Thanks
Click to expand...
Click to collapse
try booting twrp
'fastboot boot img name' then flash recovery from there. hope it works.
BJack0 said:
My device is stuck in the initial boot sequence in which the logo will show as if it is booting normally, then it will stay on this screen until it goes completely blank, at which point I have to hold the power button for a long period of time to get it back to the boot sequence. My phone is unlocked and I was trying my first time at flashing a custom recovery and OS, I flashed my device with TWRP and successfully installed it along with a flash of pixel experience, After using pixel experience I wanted to try lineage OS since it wasn't as good as I hoped, so I tried to get into the TWRP and I could not do it at all I tried every method I could search. After an hour of trying different methods of getting to twrp I tried to re-flash the recovery and that is when the phone because unresponsive and does what I have described above. I currently have access to fast boot and I dont want to go ****ing my phone up more than I have. If anyone can give me a step by step guide on how to fix this it would help so much since im new to android and I cant afford another £400 phone.
Thanks
Click to expand...
Click to collapse
Don't worry, things can be recovered easily. Until you get more knowledgeable and you understand more about flashing use this failsafe to recover from (almost) anything
Go here and get the latest fastboot ROM for your phone.
https://xiaomifirmwareupdater.com/miui/raphael/
For now make sure you get the one that matches the region for your phone.
Then follow this guide to flash it
https://c.mi.com/thread-1857937-1-1.html
Use the fastboot flashing section.
Make sure you change the flash option to 'clean all' when flashing. The default option will lock the bootloader again after flashing. If you do the default option with any ROM that is not the same region as the phone you will hard brick the phone, this is why I recommend getting the ROM that matches your phone.
When unpacking the fastboot ROM, it is a Linux/Unix zipped tarball, most Windows zip software will need to extract it twice. The first time will give you a single .tar file (if it doesn't have an extension then rename it and add .tar to the end) You will then need to extract everything from the tar file, which you give you the folder, containing the ROM data, to point the Mi Flash Tool at.
After doing this you, if you've remembered to change the flash option to 'clean all', then you'll have restored to stock and kept the bootloader unlocked. Now you're good to try again.
Keep a copy of the fastboot ROM on your PC and back everything up on your phone before flashing. Then if you get in a mess you know how to easily recover things.
Once you get more experienced there will be other things you might be able to do, depending on the situation, that allow you to get things working without losing everything and needing to start from scratch.
Thanks
Robbo.5000 said:
Don't worry, things can be recovered easily. Until you get more knowledgeable and you understand more about flashing use this failsafe to recover from (almost) anything
Click to expand...
Click to collapse
Thank you so much for the details post, I will try what you have said above and will report back with my results. I have one question if you know the answer ( My phone is the UK edition of the Mi 9T pro ) Would I need to download the global or EEA fastboot version.
BJack0 said:
Thank you so much for the details post, I will try what you have said above and will report back with my results. I have one question if you know the answer ( My phone is the UK edition of the Mi 9T pro ) Would I need to download the global or EEA fastboot version.
Click to expand...
Click to collapse
For safety download the EEA ROM.
I also suggest you immediately flash dm_verity (https://forum.xda-developers.com/k20-pro/how-to/flashing-orangefox-recovery-mi-9t-pro-t3980579), after you flash twrp, wipe data and then flash that
Sent from my Redmi K20 Pro using Tapatalk
Robbo.5000 said:
For safety download the EEA ROM.
Click to expand...
Click to collapse
Everything you said worded flawlessly and your a life saver. If you dont mind do you have a link to a set of guides on how to correctly flash a custom recovery and lineage OS? since when I try to research these guides I get 5 different versions of TWRP and lock my phone out :laugh:
ishaqtkr said:
I also suggest you immediately flash dm_verity after you flash twrp, wipe data and then flash that
Click to expand...
Click to collapse
If you dont mind me asking could you go into slightly more detial on that since I have seen orange fox but I dont understand what dm_verity is.
Please ignore all reply's above as I am going to make another separate post about lineage OS
Thank you for replying and resolving my issue.
like the title says I uninstalled the mentioned apps using adb and all of a sudden my camera stopped working so I decided for a simple restart and the device stuck in the loop ever since.
it restarts several times and open realme UI recovery and when I choose language it says " KINDLY REMINDER : system error, after select language, please select Online update(keep data) to recovery system, thanks! " .
So I did what the message said and I connect the wifi but instead of updating it says no updates found.
I also tried to wipe data but I got asked whether to retain contacts/media or format data.
I obviously tried the first one because I need the data but as expected it didn't work.
I am skeptical to clean format because I feel that I can still fix it with retaining the data.
I tried all the key combinations but only the realme UI recovery comes up . Please help me!
thank you
I don't think you'll be able to fix this without a full reflashing of the ROM using SP Tools and a format of the data partition from Recovery. You probably don't have access to full ADB now, if at all, and Fastboot won't help you recover anything. However, you should be able to rescue important files before you do this, as long as you have unlocked your bootloader.
Follow the steps here to install TWRP custom recovery. Once done, you can boot into it from fastboot by running `fastboot reboot recovery`. Once you're in TWRP, you can mount partitions so you can access them over USB from your PC.
Once you've got your important files transferred to your PC, take a full backup to be safe, then flash the stock ROM. This thread can help you do both of those things. Note that flashing the stock ROM using SP Tools will also restore the stock recovery. Once the process is done, boot right into fastboot and use it to reboot back into the stock recovery before letting it actually boot the ROM. Format your data partition (yes the whole thing). Now you can restart, and it should go through first time setup just fine.
I was going to uninstall these apps, but was too lazy. Guess lazyness is not too bad after all.
@Ricodey have you got the solution for this thing beacause i am also experiencing same issue
e_v_i_l_x_ said:
@Ricodey have you got the solution for this thing beacause i am also experiencing same issue
Click to expand...
Click to collapse
Unfortunately I had to go for the latter option of complete reset with the loss of data to get my device boot up . It seems the option to recover the device with data seems too complicated and not to mention the fact that this process is not without it's own risks. If you want an easy out from this issue I suggest that you complete format the device and have your important data backed up from now.
And Obviously I had data not backed up which I wanted on my device during this issue but it wasn't too important and I could let go of it cuz rest of my data was backed up.. but being the nerd I am, I tried to recover that data too.. but as I said it wasn't worth the time and risk for me so I chose the latter option.
Hope this helps! Do reply if you need further assistance !
Ricodey said:
Unfortunately I had to go for the latter option of complete reset with the loss of data to get my device boot up . It seems the option to recover the device with data seems too complicated and not to mention the fact that this process is not without it's own risks. If you want an easy out from this issue I suggest that you complete format the device and have your important data backed up from now.
And Obviously I had data not backed up which I wanted on my device during this issue but it wasn't too important and I could let go of it cuz rest of my data was backed up.. but being the nerd I am, I tried to recover that data too.. but as I said it wasn't worth the time and risk for me so I chose the latter option.
Hope this helps! Do reply if you need further assistance
Click to expand...
Click to collapse
for me the issue was like i just downgraded my device to the a.15 firmware after setting up i uninstalled the bloatware apps and some google apps which were not needed obviously and restarted my device and it got a bootloop, the issue of bootloop wasn't new to me i previoulsy had the same issue when i have downgraded to a.19 firmware. there is a simple fix, if you want to get rid of the bloatware apps now also you can use the disable command like.
(pm uninstall-user --user 0 ----package name---) this will not give any bootloop and can enjoy a part of RAM....
THIS WILL HELP
get in touch if need anything else