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Okay so, since I'm sort of new, I wanted to ask a few questions:
1. Is it possible to root xperia x8 with manufacturing date 11w48? At least at 95% chance. I'm a bit scared of the bricking part...
2. If it is possible, what kind of "ROM" (if I understood correctly) should I get?
3. If I get hard bricked/soft bricked what's the chance my phone will be still usable.
That's about it. Please don't rage at me for "OMG USE SEARCH BUTTON" type of thing.
I have tried doing it but no results found. Just threads and posts of people updating their.. ROMs I gues? Correct me if I typed anything wrong there.
But yeah, help would be appreciated. Thanks!
Jetboard said:
Okay so, since I'm sort of new, I wanted to ask a few questions:
1. Is it possible to root xperia x8 with manufacturing date 11w48? At least at 95% chance. I'm a bit scared of the bricking part...
2. If it is possible, what kind of "ROM" (if I understood correctly) should I get?
3. If I get hard bricked/soft bricked what's the chance my phone will be still usable.
That's about it. Please don't rage at me for "OMG USE SEARCH BUTTON" type of thing.
I have tried doing it but no results found. Just threads and posts of people updating their.. ROMs I gues? Correct me if I typed anything wrong there.
But yeah, help would be appreciated. Thanks!
Click to expand...
Click to collapse
1. You can safely root your x8 regardless of when it is manufactured, you will not brick it
2. You have 11w48 so it is very risky to unlock your bootloader, i suggest you flash ROMS that is for stock
3. If you get soft bricked you can flash the stock firmware back using flashtool or SEUS, if it is a hard brick, you need to go to the nearest Service center or use a JTAG
Swyped via Tapatalk 2
Thanks a whole bunch. I thought I cannot root because of my manufacturer date. But what is a flash ROM tho?
Jetboard said:
Thanks a whole bunch. I thought I cannot root because of my manufacturer date. But what is a flash ROM tho?
Click to expand...
Click to collapse
you can root your phone. but you can't unlock bl.
when you root your phone, you cam install cwm recovery. simply dl a rom for stock kernel and go to recovery and install(flash) the rom. remember to check the instructions first.
Just because i don't doesn't mean i can't.
All what I found until today was that if I cannot unlock BL I cannot install CWM recovery.
Maybe it is related to model - mine is Sony Xperia J. Y2012.
There is no fastboot available.
Am I wrong, can I have CWM, nandroid backup etc on stock ROM as only such one I may flash ?
F308 said:
All what I found until today was that if I cannot unlock BL I cannot install CWM recovery.
Maybe it is related to model - mine is Sony Xperia J. Y2012.
There is no fastboot available.
Am I wrong, can I have CWM, nandroid backup etc on stock ROM as only such one I may flash ?
Click to expand...
Click to collapse
this is for x8. not sure how it works on J. but yeah we don't havt fastboot either. but we can install cwm even with a locked bl. again that's for se x8.
edit: my advice is go to your phone's subforum. you'll get your answers there.
Just because i don't doesn't mean i can't.
Thank you. I understand that lot of things is device dependent but thought there are non-breakable rules, like gravity,
and what is possible to do under certain circumstances was one of them.
Need walk through XDA forum once more, maybe there is a hope.
F308 said:
Thank you. I understand that lot of things is device dependent but thought there are non-breakable rules, like gravity,
and what is possible to do under certain circumstances was one of them.
Need walk through XDA forum once more, maybe there is a hope.
Click to expand...
Click to collapse
there probably are a few unbreakable rules, but not being familiar with your device i can't guarantee that it's safe or it would work.
Just because i don't doesn't mean i can't.
Despite lot of reading I still am missing knowledge.
Question is:
What is fastboot ?
I found more than one definition of it and compiled into my own.
1.
Of course fastboot.exe is Windows binary (part of flashtool pack) which does certain type of work.
This is not what we are interested in.
2.
I concluded that:
- fastboot is one of modes into what android device can wake up. Just like linux can boot in different ways or Windows into single mode.
- this feature is encoded into boot.img, it is not separate android application.
- boot.img will work only with related kernel.img. They are like love and marriage (which is like horse and carriage - Bundy's).
- Sony sometimes disables stock boot.img to boot into this mode then without replacing boot .img it is impossible.
More comments ?
Fastboot is protocol used to update the flash filesystem in Android devices from a host over USB. It allows flashing of unsigned partition images.
Just because i don't doesn't mean i can't.
Okay, I got one more last question. Is this guide http://forum.xda-developers.com/showthread.php?t=906195&nocache=1 okay to use for rooting? I'm still trying to find the LATEST safe ones =/ I wonder if this one is okay.
Um, I tried that one it didn't work. It said some stuff are missing, then it exited randomly etc.. Can someone give me a link or a short/long guide which I can use that's latest? I do have some X8 drivers in a .zip file but no idea how to install them. Thanks in advance.
Jetboard said:
Okay, I got one more last question. Is this guide http://forum.xda-developers.com/showthread.php?t=906195&nocache=1 okay to use for rooting? I'm still trying to find the LATEST safe ones =/ I wonder if this one is good.
Click to expand...
Click to collapse
I rooted mine with this
Means its safe
Sent from my X8
Having few issues with the SuperOneClick thing... It sometimes randomly exits, tells me that some stuff are missing etc. Any help? =/
Hi all, total newb here. (Sorry I know you probably hate these kinds of threads).
I apologize in advanced if this is a very simple case / has been discussed in the forums.
I've literally read everything I can in regards to this topic but being such a total newbie at this, I'm still not 100% sure if I got this right.
So basically my phone is XT1095 - which I didn't root or unlock boatlader (simply because I don't know why), that suddenly got into a boot loop.
So on that AP Fastboot screen.
So all options (including normal powerup, recovery and factory reset) produces
'failed to validate system image.
boot up failed'.
What should I do at this point? I've read on jcase's thread that this is a simple matter of "easily fixed by flashing proper boot.img".
Where can I find the "stock boot.img"?
I know graffixnyc has KXE21.187-42 files on his website which can be flashed. Is it pre-rooted though?
Or can I just easily use bhp090808's Multi Tool to fix this?
Can it be used while the phone is still in this bricked / bootlooped condition?
Honestly I dont mind being rooted if it means getting my phone fix. But if I can get it done without rooting it then it would be 'great' since if I fail in any way I won't void my warranty.
Sorry for asking a lot of things. As you can notice, I'm totally new at this. I've successfully rooted and install a custom ROM once in my old S3 but it was only because there was a thorough step to step process.
Again, thanks in advance and I really appreciate anyone's help
Cheers.
anyone?
koflok1234 said:
anyone?
Click to expand...
Click to collapse
I wouldn't unlock or root!!! You could lose your warranty. You can try a factory reset, else return your phone for warranty
godutch said:
I wouldn't unlock or root!!! You could lose your warranty. You can try a factory reset, else return your phone for warranty
Click to expand...
Click to collapse
Not a response I expect would found from XDA
I tried factory reset but it's stuck on that screen. Fail to validate image. I think the recovery.img is corrupted?
koflok1234 said:
Not a response I expect would found from XDA
I tried factory reset but it's stuck on that screen. Fail to validate image. I think the recovery.img is corrupted?
Click to expand...
Click to collapse
I doesn't make sense to void warranty to try to fix a problem that is covered under warranty. Maybe your emmc is defective or something like that, don't make matters worse.... You unlock your device when you have verified that everything is working, not when things start failing
I am under warranty but I am currently overseas so sending the phone and process the return is a bit of a hassle. So 'other' options is to do a local repair outside warranty here but that costs a bit.
So if I can fix it myself with a simple procedure then it might be the best way.
I'm having the same issue as well if anyone has figured out how to fix this I would be extremely grateful. I am still under warranty, but I'm nervous they will send me a replacement in worse shape than my current device.
My pure edition was stuck at the splash screen and I didn't previously unlock my bootloader. I also didn't have USB debugging checked so I couldn't find my phone using ADB. Unlocking a pure edition bootloader DOES NOT VOID warranty!!! So I unlocked my bootloader and flashed the factory files and restored the use of my phone. I then updated to lollipop, rooted my phone and checked USB debugging. That way I have full control of my phone and can fix it myself if something comes up. There is the thread saying the warranty won't be void after unlock.
https://forums.motorola.com/posts/677736c888?page=2
The problem now is that it is impossible to root or do anything else with me phone that doesn't involve fastboot
sianaka said:
The problem now is that it is impossible to root or do anything else with me phone that doesn't involve fastboot
Click to expand...
Click to collapse
same here. anybody solved the issue? can we recover through fastboot? anything we can try?
this happend after trying to root the device (step 7 in multi-too to be specific
You should be able to recover via fastboot if you have the factory image, there are some floating around here.
If it's an official one you don't even need to unlock your phone because the image is signed by Moto.
Here is a link to an official guide on how to flash.
https://motorola-global-portal.custhelp.com/app/standalone/bootloader/recovery-images
pwvandeursen said:
same here. anybody solved the issue? can we recover through fastboot? anything we can try?
this happend after trying to root the device (step 7 in multi-too to be specific
Click to expand...
Click to collapse
solved.
used fastboot to flash the files from multi-tool (recovery, system boot) booted back up, only pushed root (not TWRP), an d now fully functional again
pwvandeursen said:
solved.
used fastboot to flash the files from multi-tool (recovery, system boot) booted back up, only pushed root (not TWRP), an d now fully functional again
Click to expand...
Click to collapse
Can you possibly explain this step by step? Sorry I'm kind of new to this.
Also, will I be able to do this if my battery is low?
koflok1234 said:
Hi all, total newb here. (Sorry I know you probably hate these kinds of threads).
I apologize in advanced if this is a very simple case / has been discussed in the forums.
I've literally read everything I can in regards to this topic but being such a total newbie at this, I'm still not 100% sure if I got this right.
So basically my phone is XT1095 - which I didn't root or unlock boatlader (simply because I don't know why), that suddenly got into a boot loop.
So on that AP Fastboot screen.
So all options (including normal powerup, recovery and factory reset) produces
'failed to validate system image.
boot up failed'.
What should I do at this point? I've read on jcase's thread that this is a simple matter of "easily fixed by flashing proper boot.img".
Where can I find the "stock boot.img"?
I know graffixnyc has KXE21.187-42 files on his website which can be flashed. Is it pre-rooted though?
Or can I just easily use bhp090808's Multi Tool to fix this?
Can it be used while the phone is still in this bricked / bootlooped condition?
Honestly I dont mind being rooted if it means getting my phone fix. But if I can get it done without rooting it then it would be 'great' since if I fail in any way I won't void my warranty.
Sorry for asking a lot of things. As you can notice, I'm totally new at this. I've successfully rooted and install a custom ROM once in my old S3 but it was only because there was a thorough step to step process.
Again, thanks in advance and I really appreciate anyone's help
Cheers.
Click to expand...
Click to collapse
Well i booted his file, now my device is in a bootloop. i requested the original img file from the motorola site. Search it up in google. I will try it right now. Hope it works!!!
Hi guys -
I'm somewhat a newbie here. I think I have bricked my Nexus 6. I had root and an unlocked bootloader. I had Chroma riom installed and was trying to go back to stock rom, unrooted with locked bootloader and through TWRP i deleted everything, including the OS I believe. So now my phone is locked on the Google startup screen (unlocked bootloader) . Suggestions?
Thanks -
John
if your bootloader is unlocked you should be able to fastboot clear cache and user data , then flash a rom from twrp. I would refrain from ever locking the bootloader back up since the update where you have to enable unlock bootloader in Dev Options.
droidstyle said:
if your bootloader is unlocked you should be able to fastboot clear cache and user data , then flash a rom from twrp. I would refrain from ever locking the bootloader back up since the update where you have to enable unlock bootloader in Dev Options.
Click to expand...
Click to collapse
me too I'm have Nexus 6 5.1.1 no recovery...except the bootloader that's locked Code: 2 , i can't unlock it, any solution !!?
hadifreestyler said:
me too I'm have Nexus 6 5.1.1 no recovery...except the bootloader that's locked Code: 2 , i can't unlock it, any solution !!?
Click to expand...
Click to collapse
no you are bricked unfortunately. the unlock bootlader option in dev options really seems to have caused more issues then good.
I am wondering if Jtag will fix these devices?
jpl81905 said:
Suggestions?
Click to expand...
Click to collapse
Stop.
Read.
A lot.
You have an unlocked nexus with custom recovery installed, and you don't know what to do? You shouldn't be messing with this stuff. You lack VERY basic understanding. Read the stickies.
https://developers.google.com/android/nexus/images?hl=en
Factory images. Follow their directions.
scryan said:
Stop.
Read.
A lot.
You have an unlocked nexus with custom recovery installed, and you don't know what to do? You shouldn't be messing with this stuff. You lack VERY basic understanding. Read the stickies.
https://developers.google.com/android/nexus/images?hl=en
Factory images. Follow their directions.
Click to expand...
Click to collapse
Thank you. I think.
jpl81905 said:
Hi guys -
I'm somewhat a newbie here. I think I have bricked my Nexus 6. I had root and an unlocked bootloader. I had Chroma riom installed and was trying to go back to stock rom, unrooted with locked bootloader and through TWRP i deleted everything, including the OS I believe. So now my phone is locked on the Google startup screen (unlocked bootloader) . Suggestions?
Thanks -
John
Click to expand...
Click to collapse
The easiest way if you are not familiar with ADB is to download the nexus tool kit located on these forums from WUGFRESH. That tool will walk you through a step by step process on how to flash stock back. You are far from bricked. I have deleted my entire phone many a times and just re flashed stock back easily. As long as your boot loader is unlocked you are fine
Link to toolkit: http://www.wugfresh.com/nrt/
The option you are going to want to use is on the front of the toolkit called flash stock + un-root. You can watch some videos on his website as well for flashing stock. That is all you need to do .
Any questions let me know, send me a PM
backdown00 said:
The easiest way if you are not familiar with ADB is to download the nexus tool kit located on these forums from WUGFRESH. That tool will walk you through a step by step process on how to flash stock back. You are far from bricked. I have deleted my entire phone many a times and just re flashed stock back easily. As long as your boot loader is unlocked you are fine
Link to toolkit: http://www.wugfresh.com/nrt/
The option you are going to want to use is on the front of the toolkit called flash stock + un-root. You can watch some videos on his website as well for flashing stock. That is all you need to do .
Any questions let me know, send me a PM
Click to expand...
Click to collapse
It is not the easiest option. The easiest option is plug the USB cable in, boot to TWRP, enable MTP mode and copy a rom to the sdcard.
Also, many senior members here will discourage the use of toolkits for those who are not familiar with adb or fastboot. It is best to learn these and use them at least once before starting to use toolkits. Toolkits do not "walk you through". They take you through without explaining anything.
danarama said:
It is not the easiest option. The easiest option is plug the USB cable in, boot to TWRP, enable MTP mode and copy a rom to the sdcard.
Also, many senior members here will discourage the use of toolkits for those who are not familiar with adb or fastboot. It is best to learn these and use them at least once before starting to use toolkits. Toolkits do not "walk you through". They take you through without explaining anything.
Click to expand...
Click to collapse
In a perfect world, I am sure we would all love to dive in and discover everything and be experts in all fields as time would not be a factor. I do not disagree it is helpful to learn ADB and fastboot commands and understand what they do. At this point in time though, the end goal here is to get his phone back up and running as fast as possible and then he can do the post-mortem to figure out what he did wrong and how to fix it .
I am guessing hes not very familiar with TWRP since he wound up in this situation. The toolkit alleviates the need for knowledge and gets the job done. I'm sure after this, the OP will research how to use his phone before trying to do anything next.
backdown00 said:
In a perfect world, I am sure we would all love to dive in and discover everything and be experts in all fields as time would not be a factor. I do not disagree it is helpful to learn ADB and fastboot commands and understand what they do. At this point in time though, the end goal here is to get his phone back up and running as fast as possible and then he can do the post-mortem to figure out what he did wrong and how to fix it .
I am guessing hes not very familiar with TWRP since he wound up in this situation. The toolkit alleviates the need for knowledge and gets the job done. I'm sure after this, the OP will research how to use his phone before trying to do anything next.
Click to expand...
Click to collapse
..but even so, your method is overkill. It is really simple to boot into TWRP and look in the menu for the "Enable MTP" option. Once that is done, the phone appears in "Computer" as an MTP device, just like when you boot into android. Then, simply dragging and dropping a ROM onto that device then flashing it via recovery will get him back up and running. There is nothing simpler or quicker than this.
Sorry, I do not intend to be confrontational here.
The title explains it all. I got this phone knowing I could root and install CFW, but wanted to just "use" it for a few days in stock. I don't mind stock, I would jsut prefer a custom firmware. I'm having trouble figuring out what I need to do to downgrade to Lollipop so I can flash TWRP and begin using CFW. A simple set of instructions would be very appreciated. Thanks to anyone who can help!
but2002 said:
The title explains it all. I got this phone knowing I could root and install CFW, but wanted to just "use" it for a few days in stock. I don't mind stock, I would jsut prefer a custom firmware. I'm having trouble figuring out what I need to do to downgrade to Lollipop so I can flash TWRP and begin using CFW. A simple set of instructions would be very appreciated. Thanks to anyone who can help!
Click to expand...
Click to collapse
There appear to be guides here for doing those things with 6.0 installed, such as MicroMod777's guides.
After a few more hours of digging, I figured it out. I may draw up a cleanly laid out guide referencing the posts that helped me for people in the position I was.
Thank you!
No, you don't need to downgrade, just go ahead and install TWRP & CFW.
Careful with downgrading, becuz H811 has Q-Fuse enabled, if you mess up you'll end up with a 9008 hard brick
im having a similar issue im trying to root/unlock 20p and its not finding any device in fastboot it just sits there saying locating any device and never locates anything adb see's the phone just fine anyone know anything about that? thanks for the help in advance
Rooting stock G4H811 already on 20p?
but2002 said:
After a few more hours of digging, I figured it out. I may draw up a cleanly laid out guide referencing the posts that helped me for people in the position I was.
Thank you!
Click to expand...
Click to collapse
Yea, I'm trying to root my new updated G4 that's on 20p. I have one that's soft bricked already that I'm trying to fix and don't wish to brick another.
Can someone point me in the right direction?
Thanks
Im in the same boat. No devices found after fastboot. Any advice?
Hi everyone,
Please forgive any n00b questions.
I got started with rooting / custom ROMs on a Nexus 4, and I didn't realize at the time that this made things really easy and I didn't need to learn very much about how everything worked. Fast forward to last week -- I decided, at long last, that I was tired of using stock MM on my T-Mo G4 / H811. How hard could it be? Probably not much different from playing on my old Nexus 4 right? Lol, maybe not.
So now 72 hours later, my phone is hard bricked and will not enter download mode. and I need some assistance, if anyone would be so kind.
I will try to recount what I did:
To start with, I was using a Mac, so I used Homebrew to install Android platform tools / ADB.
I decided I wanted to try out LineageOS so I went ahead and followed their very clear steps (on LOS wiki) to unlock the bootloader install TWRP. However, TWRP doesn't seem to have an official build for the G4(!) so I had to look up and use one of the betas from this post. Is this where I went off the rails already? [Of course, very stupidly I also failed to make a complete backup of anything before going on ahead. Rookie mistake.]
After unlocking bootloader and flashing my TWRP beta, I was able to boot into TWRP just fine. I followed the normal prescribed steps of doing a Wipe (normal TWRP defaults -- system, cache, etc.?) before flashing the latest LOS nightly (14.1-something) and also the nano-x64 variety of gapps. I rebooted and got stuck with the LOS boot animation. I let this go for 55 minutes, so I am pretty sure it was an actual bootloop, not just the 1st-time-startup and optimization going on.
I rebooted into TWRP and decided to try a different ROM to see if that was the issue. So I wiped again, flashed another ROM (I believe it was a flavor of AOKP 14.1.x), flashed gapps again, and gave it another try. Again got stuck with an endless bootloop (45 minutes).
Since this is my daily driver, I decided to go back to stock. Found this thread, downloaded the MM-debloated zip, pushed to phone, and again Wiped + Flashed. This time, when I hit reboot, my phone was immediately hard-bricked. No startup screen, no nothing. That was quite unexpected. Also, the first time I had ever HARD bricked a device that I was playing with. Yikes!
Since then, I got a hold of a PC, and have been trying to revive the device by flashing an image to the microSD and booting into Download mode, in the form of this thread or this one.
I did get this to work briefly yesterday, or at least I got to Download Mode / Firmware Update screen, and then attempted to run LGUP with the KDZ file. However I ran into an error at about 9%, and couldn't continue -- and then I had to give back my loaner PC for the day. I also noticed that the LG Mobile Support tool was recognizing my phone NOT as an H811 but as something like HX230 or ... whatever it was, it was definitely wrong. Which is worrisome.
Today I'm giving it another try but my phone will not enter Download Mode at all, nor respond in any other way. I'm curious if this is a battery issue? So I am simply charging it for the time being. I also re-formatted the microSD and re-flashed the single .img just to be safe, but still can't get a response out of the phone. On my PC's device manager it is showing up as the common Qualcomm 9008 that a lot of people seem to have seen. No recognition from LG Mobile Support tool, nor from LGUP.
So ... what now?
It's possible that once my battery gets some charge again, maybe I'll be able to enter DL mode. Let's hope so.
However, I am also totally in the dark about which software version I should be using. 20i? 20p? I have no idea what these refer to, and I did not make any prior notes to capture the state that my phone was in before this all began. So IF I get to DL mode I will definitely need further instruction on the CORRECT KDZ FILE to be flashing. Else I will just compound my problems.
ANY tips or suggestions will be appreciated! Thanks so much.
Should have verified being on 20o firmware
Upon further reading, quite obvious, at the top of this thread, I definitely should have followed the Prerequisite steps. I did NOT verify that I was on 20o firmware. "OR RISK BRICKING YOUR DEVICE" is right.
So I bricked my device, in exactly the way I was warned not to do, it seems.
Still, what's the next step? Any thoughts?
freeradical426 said:
Upon further reading, quite obvious, at the top of this thread, I definitely should have followed the Prerequisite steps. I did NOT verify that I was on 20o firmware. "OR RISK BRICKING YOUR DEVICE" is right.
So I bricked my device, in exactly the way I was warned not to do, it seems.
Still, what's the next step? Any thoughts?
Click to expand...
Click to collapse
try search for a fix if not may be @steadfasterX knows how to help you.
Re: searching for unbrick solutions
raptorddd said:
try search for a fix if not may be @steadfasterX knows how to help you.
Click to expand...
Click to collapse
Thanks, I have been looking around for solutions, but can't seem to find anything aside from the unbrick-guides that I've already listed / already attempted.
Will hope for help from @steadfasterX ! Or some other knowledgeable / benevolent party.
freeradical426 said:
Thanks, I have been looking around for solutions, but can't seem to find anything aside from the unbrick-guides that I've already listed / already attempted.
Will hope for help from @steadfasterX ! Or some other knowledgeable / benevolent party.
Click to expand...
Click to collapse
Ok what was the last KDZ file you flashed which had worked? 20o?
As you have hard bricked your device you can try the sdcard method again if it works flash 20o again (of it it was 20o).
If you flash a lower version you will hard brick again.
If the sdcard doesn't work anymore for you you can try to flash with QFIL but beware to use the right one. If you use the wrong one it will convert your device and believe me that's not what you want. I can share the good ones but unfortunately maybe on next week first.
Otherwise search on your own for 9008 unbrick but check the md5sum of the programmer!! Compare it with the Evil one mentioned in my ARB list here: http://tinyurl.com/antirollg4 and DO NOT USE THE EVIL one..
Sent from my LG-H815 using XDA Labs
steadfasterX said:
Ok what was the last KDZ file you flashed which had worked? 20o?
As you have hard bricked your device you can try the sdcard method again if it works flash 20o again (of it it was 20o).
If you flash a lower version you will hard brick again.
If the sdcard doesn't work anymore for you you can try to flash with QFIL but beware to use the right one. If you use the wrong one it will convert your device and believe me that's not what you want. I can share the good ones but unfortunately maybe on next week first.
Otherwise search on your own for 9008 unbrick but check the md5sum of the programmer!! Compare it with the Evil one mentioned in my ARB list here: http://tinyurl.com/antirollg4 and DO NOT USE THE EVIL one..
Click to expand...
Click to collapse
Thanks very much for the guidance! The post that you linked to REALLY helps. Until now I really was not sure what 10n, 20i, 20o, etc. referred to, aside from just various software versions. Having a definition for anti-rollback and further links to explain, really helps! This gives me more information and I might be able to self-resolve from here. I will give it a shot.
As for your question ... unfortunately there was NO instance where I flashed a working KDZ file, and I didn't know (due to my past experience with my Nexus) that I needed to check the STOCK software version of my phone before beginning to play with ROMs. In other words, I have no idea if I was on 20i, 20o, 20p, etc. From what I understand, this makes things a lot more difficult
Having looked at the linked thread just a little bit, it appears that using a 20o KDZ is the best bet -- because I bricked my device using a 20i ROM so I expect it was due to violating the anti-rollback restriction.
I will look into it more closely and come back if I hit another brick wall. Thanks so much!
If anyone cares, here are the ending results of all this ...
#1 Be wary of anti-rollback restrictions before you flash anything to your G4. You WILL brick your phone!
I tried multiple rounds and multiple variations of all the MicroSD card methods that I could find. I could NOT succeed in unbricking my phone.
#2 Luckily ... I was able to convince LG that I was still technically under warranty!
Because I had the stock bootloop issue in May 2017, LG did an in-warranty repair for me, and replaced the motherboard. So last week, I simply told them "my phone is AGAIN unable to charge and will not power on, just like in May". Since it had only been 5-6 months since the first issue, they agreed to replace the motherboard again.
Moral of the story: you can definitely unbrick your phone by having LG replace the mobo XD XD
From here, I think I will just totally avoid doing any rooting or custom ROMs on my totally-stock G4 coming today in the mail. I will cross my fingers and hope we get OEM Nougat in the USA sometime in the next couple of months.
Thanks again for the help everyone!