Database Develop

[Q] NAND write start!! Fail

Hi All,
I have a Samsung S5 Mini (SM-G800h), I am trying to update its firmware using ODIN but I keep getting "system.img.ext4"
<ID:0/008> system.img.ext4
<ID:0/008> Fail
<OSM> All threads completed. (succeed 0 / failed 1)
I have tried all firmwares available on SamMobile on different PCs using different USB cables and different Odin Versions with no luck. I keep getting the same message all the time. (and the USB Debugging is on)
Can anyone help in this please?????????

moamh1 said:
Hi All,
I have a Samsung S5 Mini (SM-G800F), I am trying to update its firmware using ODIN but I keep getting "NAND START Fail"
<ID:0/008> NAND Write Start!!
<ID:0/008> Fail
<OSM> All threads completed. (succeed 0 / failed 1)
I have tried all firmwares available on SamMobile on different PCs using different USB cables and different Odin Versions with no luck. I keep getting the same message all the time. (and the USB Debugging is on)
Can anyone help in this please?????????
Click to expand...
Click to collapse
You need download firmware and ODIN from this page and do like instruction says.
sammobile.com/firmwares/3/?download=31721
If you still have a problems - try change computer, sometimes problem not in device. I was repair my S5mini couple time.

Winstrol said:
You need download firmware and ODIN from this page and do like instruction says.
sammobile.com/firmwares/3/?download=31721
If you still have a problems - try change computer, sometimes problem not in device. I was repair my S5mini couple time.
Click to expand...
Click to collapse
Thanks .. but I downloaded all the firmwares on Sammobile and tried 4 or 5 pcs, same problem all the time.
Does anyone have an idea why this is happening or what causes it?

moamh1 said:
Thanks .. but I downloaded all the firmwares on Sammobile and tried 4 or 5 pcs, same problem all the time.
Does anyone have an idea why this is happening or what causes it?
Click to expand...
Click to collapse
look is like your phone was locked before you start update.
it can be operator version or some one started option in Setting\Security\Reactivation lock - this option dont give you choice reinstalling OS

Winstrol said:
look is like your phone was locked before you start update.
it can be operator version or some one started option in Setting\Security\Reactivation lock - this option dont give you choice reinstalling OS
Click to expand...
Click to collapse
Thanks Winstrol for the prompt response. The phone does not even have a reactivation lock option int he Security menu.
Its really weird that all I get is Fail after the Nand write Start, any idea to try?

just for clear - did you try to change you computer and do it on another PC?

Winstrol said:
just for clear - did you try to change you computer and do it on another PC?
Click to expand...
Click to collapse
I have tried 3 different Pc's and also tried like 5 or 6 different usb cables, still no luck! Getting frustrated with it .. its just weird..
I need to know what can cause such a problem?!?

Having almost the same problem. SM-G800F. Trying to flash the latest stock firmware (SER-G800FXXU1ANG1-20140709112536.zip / G800FXXU1ANG1_G800FSER1ANG1_G800FXXU1ANG1_HOME.tar.md5). Odin 3.09 and 3.07 both are stopping on the same file: system.img. Tried different USB cables and two more firmwares for other regions.
Maybe it is necessary to try to re-partition with PIT file? Is it possible to find it somewhere?

Alex Sad said:
Having almost the same problem. SM-G800F. Trying to flash the latest stock firmware (SER-G800FXXU1ANG1-20140709112536.zip / G800FXXU1ANG1_G800FSER1ANG1_G800FXXU1ANG1_HOME.tar.md5). Odin 3.09 and 3.07 both are stopping on the same file: system.img. Tried different USB cables and two more firmwares for other regions.
Maybe it is necessary to try to re-partition with PIT file? Is it possible to find it somewhere?
Click to expand...
Click to collapse
I am now facing the same problem that you are facing, I now have the two versions of the S5 Mini 1: sm-g800f and 2: sm-g800h (dual sim). I have tried all available firmwares at sammobile for both phones using different pcs, cables and odin versions, I always get Fail after 5-10 seconds from the system.img.ext4 start.
Any help?

Have u stopped all Kies services in the Taskmanager before flashing?

NikePershing said:
Have u stopped all Kies services in the Taskmanager before flashing?
Click to expand...
Click to collapse
I don't even have it installed on my PC and I have stopped it on the other ones that I have used, still no luck, same error every time. It always fails just when it gets to the system.img.ext4.
Any idea ?

moamh1 said:
I don't even have it installed on my PC and I have stopped it on the other ones that I have used, still no luck, same error every time. It always fails just when it gets to the system.img.ext4.
Any idea ?
Click to expand...
Click to collapse
I have to say that I have flashed a Grand 2 on the same pc using the same USB cable and that worked fine.

moamh1 said:
I have to say that I have flashed a Grand 2 on the same pc using the same USB cable and that worked fine.
Click to expand...
Click to collapse
This is Odin's log:
<ID:0/007> Added!!
<OSM> Enter CS for MD5..
<OSM> Check MD5.. Do not unplug the cable..
<OSM> Please wait..
<OSM> G800HXXU1ANGF_G800HODD1ANGB_G800HXXU1ANGH_HOME.tar.md5 is valid.
<OSM> Checking MD5 finished Sucessfully..
<OSM> Leave CS..
<ID:0/007> Odin v.3 engine (ID:7)..
<ID:0/007> File analysis..
<ID:0/007> SetupConnection..
<ID:0/007> Initialzation..
<ID:0/007> Get PIT for mapping..
<ID:0/007> Firmware update start..
<ID:0/007> SingleDownload.
<ID:0/007> aboot.mbn
<ID:0/007> NAND Write Start!!
<ID:0/007> sbl1.mbn
<ID:0/007> rpm.mbn
<ID:0/007> tz.mbn
<ID:0/007> sdi.mbn
<ID:0/007> NON-HLOS.bin
<ID:0/007> boot.img
<ID:0/007> recovery.img
<ID:0/007> system.img.ext4
<ID:0/007> FAIL! (Ext4)
<ID:0/007>
<ID:0/007> Complete(Write) operation failed.
<OSM> All threads completed. (succeed 0 / failed 1)

Are you trying to flash SM-G800H firmware on a SM-G800F? They are not the same device. lt won't work.
Sent from my SM-P605 using XDA Free mobile app

polyconvex said:
Are you trying to flash SM-G800H firmware on a SM-G800F? They are not the same device. lt won't work.
Sent from my SM-P605 using XDA Free mobile app
Click to expand...
Click to collapse
To be honest with you, out of desperation at the end I have tried it (no luck off course), but I have originally flashed SM-G800H with SM-G800H firmwares. These are the ones that I have tried, I got the same error with all (using different PCs, Odin versions and USB cables):
Model Country/Carrier Date Version PDA CSC
SM-G800H India 2014 July 4.4.2 G800HXXU1ANGF G800HODD1ANGB
SM-G800H Russia 2014 July 4.4.2 G800HXXU1ANGD G800HOXY1ANGD
SM-G800H UAE 2014 July 4.4.2 G800HXXU1ANGF G800HOJV1ANG5
SM-G800H Egypt 2014 July 4.4.2 G800HXXU1ANGF G800HOJV1ANG5
SM-G800H South Africa 2014 July 4.4.2 G800HXXU1ANGF G800HOJV1ANG5
SM-G800H Afghanistan 2014 July 4.4.2 G800HXXU1ANGF G800HOJV1ANG5
SM-G800H Saudi Arabia 2014 July 4.4.2 G800HXXU1ANGF G800HOJV1ANG5
SM-G800H Guatemala 2014 July 4.4.2 G800HXXU1ANGG G800HUWA1ANG1
SM-G800H Trinidad and T 2014 July 4.4.2 G800HXXU1ANGG G800HUUB1ANFE
SM-G800H Panama 2014 July 4.4.2 G800HXXU1ANGC G800HUUB1ANFE
SM-G800H Russia 2014 July 4.4.2 G800HXXU1ANGA G800HOXY1ANGA
SM-G800H Brazil 2014 July 4.4.2 G800HXXU1ANGC G800HZTO1ANG1

Does anyone have an idea what to do? still getting the same error and on the phone screen it states: Odin invalid ext4 image

Guys, pleas tell, what you did with your phones before trying to flash? Just for clear - which reasons did you have for reflashing?

Winstrol said:
Guys, pleas tell, what you did with your phones before trying to flash? Just for clear - which reasons did you have for reflashing?
Click to expand...
Click to collapse
for me it was getting a problem with it freezing the screen, a friend of mine brought it for me from abroad so I couldn't benefit from the warranty. Therefore, I thought the best option would be just to flash it with the latest firmware available. I have done this several times with other phones with no problem, no sure why i am facing this problem with this one (actaully its now the two of them), cause i tried the same with my friends phone, same result !!

Still have no idea why it is happen.. but when we try rooting SM-800F and made several versions of ROM by several different compilations we have same problems - stopped flashing at system.bin. Just one from several versions got work and was flashed normaly and got a root on my device - i putted this version in the post here
For sure - who have problem and have SM-800F try to flash this version.

Winstrol said:
Still have no idea why it is happen.. but when we try rooting SM-800F and made several versions of ROM by several different compilations we have same problems - stopped flashing at system.bin. Just one from several versions got work and was flashed normaly and got a root on my device - i putted this version in the post here
For sure - who have problem and have SM-800F try to flash this version.
Click to expand...
Click to collapse
Thanks for the update but any solution for the SM-800H?

[Q] Soft-bricked S5 G900A after downgrading from OA1

Hi all. Long time reader, first time poster.
I was rooted on NG3 and figured I'd downgrade to NCE so I could get the 4.4.4 update. 4.4.4 wouldn't update in that condition and I wanted to ensure I'd be able to get Lollipop (it is coming, AT&T, right?). I backed up everything in Kies, downgraded to NCE and took the OTA to 4.4.4. All was well and then when I went to restore my backup from Kies, it told me I could backup everything except my apps. Being lazy, I figured I'd start all over and do the restore of all my apps while still on 4.4.2, then take the OTA to 4.4.4 again.
I started all over using the method linked below, but after Odin finishes and the S5 reboots, the Samsung splash logo animation almost finishes, pauses for a few seconds and the screen goes black and the notification LED is on blue and becomes non-responsive.
I've tried going into recovery and wiping cache and data and starting the Odin process linked below again with the same results for the past 3-4 hours. I've tried Kies update and initialization but that tells me my phone isn't compatible. Did 4.4.4 do something with the boot-loader and now it's incompatible with 4.4.2?
Any ideas or other options? Thanks in advance!
HTML:
http://forum.xda-developers.com/showthread.php?t=2785363
This was linked from a factory reset thread I believe.
ODIN MODE
PRODUCT NAME: SM-G900A
CURRENT BINARY: Samsung Official
SYSTEM STATUS: Official
REACTIVATION LOCK(KK): OFF
KNOW WARRANTY VOID: 0x0
QUALCOMM SECUREBOOT: ENABLE (CSB)
AP SWREV: S1, T1, A1, A2, P1
SECURE DOWNLOAD : ENABLE
UDC START
Here are the last few lines from Odin:
<ID:0/006> modem.bin
<ID:0/006> Transmission Complete..
<ID:0/006> Now Writing.. Please wait about 2 minutes [at this point it was less than a minute to get to the end]
<ID:0/006> Receive Response from boot-loader
<ID:0/006> cache.img.ext4
<ID:0/006> RQT_CLOSE !!
<ID:0/006> RES OK !!
<ID:0/006> Remain Port .... 0
<OSM> All threads completed. (succeed 1 / failed 0)
<ID:0/006> Removed!! [It is in Boot Recovery Mode when this happens]

Fixed!
Okay, I think I'm back up thanks to another thread similar to mine posted recently. For anyone that is downgrading to NCE from OA1, use the G900A_Downgrade_to_NCE.tar in the 4.4.4 root thread. Do NOT use the method that contains 4 files (BL, AP, CP, CSC). The 4 stock files worked great from NG3 to NCE, but not so well from OA1, as you can see above.

TheeDesecrator said:
Okay, I think I'm back up thanks to another thread similar to mine posted recently. For anyone that is downgrading to NCE from OA1, use the G900A_Downgrade_to_NCE.tar in the 4.4.4 root thread. Do NOT use the method that contains 4 files (BL, AP, CP, CSC). The 4 stock files worked great from NG3 to NCE, but not so well from OA1, as you can see above.
Click to expand...
Click to collapse
It was my thread wasn't it.

ElectricBiskitz said:
It was my thread wasn't it.
Click to expand...
Click to collapse
Indeed it was. Mine was originally in AT&T General before it got moved. If were in the right place the first time, I wouldn't have needed to start a new thread. Hope both threads help people trying the same thing as us, though.

Soft Brick Bootloop HELP

Hi guys, I could really use some help here.
I have a Samsung Galaxy S5, yesterday I used Odin 3.10 to root my phone. I rooted it using 'CF-Auto-Root-kltespr-kltespr-smg900p.tar'. 5.0, Lollipop
It appeared to work just fine and booted fine. I then attempted to flash the TWRP ROM, with Odin 3.10, using twrp-klte.tar.md5.
Again, it booted fine.
After this I was trying to install a module on the Xposed installer app but it told me the framework was not installed.
SO, I installed the framework, again using Odin 3.10. with xposed-v81-sdk21-arm (it was version 80 something)
Now It's bootlooped/softbricked.
I've already tried wiping all the cache and gavlik (sp?), I've tried resetting to factory settings, I've tried re installing the custom rom, I've even tried downloading the original stock rom. Nothing works. I've waited 10-15mins with each different thing I've installed and it still just sits on the Sprint spark screen.
I'm now at the current point where, when I go into recovery mode, it seems to be the old stock rom (Teamwin screen no longer appears) and I did cache resets here and factory reset and rebooted and again it's been half an hour on the Sprint Spark screen.
Am I missing something? If anyone can please suggest a working solution I'd really appreciate it.

Which framework? You have to use Wanam Xposed or Systemless Xposed by Topjohnwho because the official version by Rovo bootloop on Samsung devices.
http://forum.xda-developers.com/showthread.php?t=3180960
Sent from my lightning fast SM-G930F (S7)
---------- Post added at 01:45 AM ---------- Previous post was at 01:43 AM ----------
You have to install the Wanam Xposed zip in twrp.
Sent from my lightning fast SM-G930F (S7)
---------- Post added at 01:51 AM ---------- Previous post was at 01:45 AM ----------
If everything fails download stock rom from Sammobile and install stock rom again with odin pc. Then install twrp and root again. Then install Wanam arm xposed version.
I had an S5 in the past and I remember that sometimes in TWRP recovery the message appears to install stock recovery again do not do that.
Sent from my lightning fast SM-G930F (S7)

Thanks for the reply.
I actually just finished downloading the Stock rom, I ran it through odin 3.11 and now I'm getting the following error
The stock rom I downloaded was G900PVPU1BOA6_G900PSPT1BOA6_G900PVPU1BOA6_HOME.tar.md5 (Samsung Galaxy S5 SMG-900P
This is the error I''m getting. So now it won't even install the Stock ROM
<ID:0/004> Added!!
<OSM> Enter CS for MD5..
<OSM> Check MD5.. Do not unplug the cable..
<OSM> Please wait..
<OSM> Checking MD5 finished Sucessfully..
<OSM> Leave CS..
<ID:0/004> Odin engine v(ID:3.1101)..
<ID:0/004> File analysis..
<ID:0/004> SetupConnection..
<ID:0/004> Initialzation..
<ID:0/004> Get PIT for mapping..
<ID:0/004> Firmware update start..
<ID:0/004> SingleDownload.
<ID:0/004> aboot.mbn
<ID:0/004> NAND Write Start!!
<ID:0/004> FAIL! (Auth)
<ID:0/004>
<ID:0/004> Complete(Write) operation failed.
<OSM> All threads completed. (succeed 0 / failed 1)

Ok.... update
So I was able to boot into recovery and it shows I have TWRP v2.7.0.0
So now how do I install Wanama's xposed v86? I've downloaded it. Do I just do it through odin again?

Ok so I figured how to load xposed-uninstaller through adb onto my sd card. installed it through twrp and cleared the davlik cache or whatever it's called, rebooted and bootloop fixed!
HOWEVER, that wanam x86 sdk 22 xposed doesn't work. I tried installing that through TWRP and it told me it's the wrong version
Thanks so much for your help!
Should I just upgrade my firmware to marshmellow and then root and install xposed that way?? would that be easier?

Bazerk83 said:
xposed-v81-sdk21-arm (it was version 80 something)
Click to expand...
Click to collapse
Bazerk83 said:
wanam x86 sdk 22 xposed
Click to expand...
Click to collapse
If you're going to keep flashing things at random, no one is going to be able to save you.

Bazerk83 said:
Ok so I figured how to load xposed-uninstaller through adb onto my sd card. installed it through twrp and cleared the davlik cache or whatever it's called, rebooted and bootloop fixed!
HOWEVER, that wanam x86 sdk 22 xposed doesn't work. I tried installing that through TWRP and it told me it's the wrong version
Thanks so much for your help!
Should I just upgrade my firmware to marshmellow and then root and install xposed that way?? would that be easier?
Click to expand...
Click to collapse
Flash the stock firmware via Odin
Put the new custom rom on your sd card
Install a custom recovery
Wipe cache
Flash the ROM
Let your phone boot and wait for the rom to settle
Go back to recovery and install the frameworks compatible with your phone (have the uninstall zip on sd card just in case something goes wrong)
Boot
Install Xposed apk
Everything should work just fine

Stock Official ATT_ODIN_N960USQU1ARG9 Note9

Stock Official ATT_ODIN_N960USQU1ARG9 Note9
Model: SM-N960U
Model Name: Galaxy Note9
Country: USA
Version: Android Oreo 8.1.0
Security Patch Level: July 1st, 2018
Product Code: ATT
PDA: N960USQU1ARG9
CSC: N960UOYN1ARG9
Download here: AT&T N960USQU1ARG9
MD5: 92461b75fbee75796b979b45e52b0658
Download here: Odin3_v3.13.1_3B_PatcheD

Link up.
Running On My Galaxy S9+ SM-G965U Wicked Venom

Any root info yet for the att note 9,or if the safestrap recovery for the note 8 will work on the note 9

gubbilo144 said:
Any root info yet for the att note 9,or if the safestrap recovery for the note 8 will work on the note 9
Click to expand...
Click to collapse
No information on this and Safestrap will not work on Oreo 8.1
Running On My Galaxy S9+ SM-G965U Wicked Venom

THANK YOU!!! Any special way of flashing it?

Getting this... Any idea why?
<ID:0/012> Added!!
<ID:0/012> Removed!!
<ID:0/013> Added!!
<OSM> Enter CS for MD5..
<OSM> Check MD5.. Do not unplug the cable..
<OSM> Please wait..
<OSM> Checking MD5 finished Sucessfully..
<OSM> Leave CS..
<ID:0/013> Odin engine v(ID:3.1301)..
<ID:0/013> File analysis..
<ID:0/013> Total Binary size: 135 M
<ID:0/013> SetupConnection..
<ID:0/013> Initialzation..
<ID:0/013> Set PIT file..
<ID:0/013> DO NOT TURN OFF TARGET!!
<ID:0/013> FAIL!
<ID:0/013>
<ID:0/013> Re-Partition operation failed.
<OSM> All threads completed. (succeed 0 / failed 1)

after i download the att odin file, i can't extract the files. it says file is corrupt, i downloaded 4 times, all same.
i have an unlocked 960u1 unlocked usa note 9 variant and want to install ATT stock firmware.
is it possible to do it?

On another thread you posted the TMO firmware. You said that if you don't use the USERDATA file and then Factory Reset then it'll automatically get your Carriers bloatware and features. I'm planning to install this on my USA unlocked note 9 so I can get the ATT HD Voice, Wifi calling, etc. What would be the difference if I use or don't use the USERDATA file from this?

Can we get a re-upload or mirror? The one available is corrupted.

truciet said:
Can we get a re-upload or mirror? The one available is corrupted.
Click to expand...
Click to collapse
Reuploading Again will Let you know when it's up. Thanks For Reporting :good:

truciet said:
Can we get a re-upload or mirror? The one available is corrupted.
Click to expand...
Click to collapse
First Post Link Updated , Please Report back!

firepowr said:
On another thread you posted the TMO firmware. You said that if you don't use the USERDATA file and then Factory Reset then it'll automatically get your Carriers bloatware and features. I'm planning to install this on my USA unlocked note 9 so I can get the ATT HD Voice, Wifi calling, etc. What would be the difference if I use or don't use the USERDATA file from this?
Click to expand...
Click to collapse
I'm wondering same

Venom0642 said:
First Post Link Updated , Please Report back!
Click to expand...
Click to collapse
It works now! Thank you!

truciet said:
It works now! Thank you!
Click to expand...
Click to collapse
Your Welcome, thanks for reporting [emoji106][emoji106]
Running On My Galaxy Note9 SM-N960U Wicked Venom

Does this odin come with your stock wallpapers @Venom0642? I wanna be sure that I have the latest update of Android and some decent looking girls on my phone.

mammothjojo88 said:
Does this odin come with your stock wallpapers @Venom0642? I wanna be sure that I have the latest update of Android and some decent looking girls on my phone.
Click to expand...
Click to collapse
Lol no private property [emoji23][emoji23]??
Running On My Galaxy Note9 SM-N960U Wicked Venom

Downloaded and did not find a home CSC file?

Anyone know if I could flash the AT&T files on the international N960F model? Was hoping to get LTE, wifi calling/HD Voice.
What would my results be if I did flash?
Thank you in advance for any knowledge you could provide me.

guys, i haven't touched an android phone since note 3, 5 years ago.
please correct me if i'm wrong:
i got unlocked n960u1, unlocked usa note 9.
i'm trying to:
1) download odin (i believe it's version 3.3 patched)
2) download and install samsunng usb drivers
3) download ATT stock firmware (from this thread)
4) enable developer options on my phone by tapping baseband version 10 times (already done)
5) phone on download mode by holding vol down + byxby + power
6) connect phone to pc via usb
7) extract att stock firmware zip file. select each file (bl, csc, etc) to odin
8) start with oding after clicking on each individual module from the att stock firmware.
9) voila!
now, question:
is all of this correct?
i believe my phone has a locked bootloader, so would the above steps work? or do i need something like safestrap? (this is what i used to custom rom my note 3 back in the days).
can i flash att firmware into my phone even though the bootloader is locked?

nycalex said:
is all of this correct?
i believe my phone has a locked bootloader, so would the above steps work? or do i need something like safestrap? (this is what i used to custom rom my note 3 back in the days).
can i flash att firmware into my phone even though the bootloader is locked?
Click to expand...
Click to collapse
Yes, to all of your questions. You just need to boot into recovery.

Downgrading A71 firmware from bootloader(BIT 3)

Hi All!
I have tried to downgrade from my A71 without any success. Most probably reason is that my phone has firmware (bit 3). If anyone wondering why downgrading, here's reason: My car has support for only Mirrorlink (no Android auto). Samsung has stopped supporting Mirrorlink June 2020. Resetting factory setting with newer firmware than May 2020 --> Mirrorlink disappears. I know that there is lot of old phones with this support which could be bought second handed but where's the fun of that ?
Is it possible to downgrade firmware from Bit 3 to Bit 1/2?
Is this Bit information saved into phone way that it cannot to be rewritten?
I'm thinking following process:
* Flash NcX 2.5 A71 ROM with TWRP --> Getting TWRP for flashing
* Format/system wipe? Is it needed?
* Using TWRP flashing Bit1 stock rom into phone from memorycard
* One zip file which includes BL, AP, CP, CHC ? Or every file extracted from zip file?
Any comments, ideas are most appreciated!!
BR JHS
HERE's what I have tried now
Here's list of firmwares which are available for my A71 and info how the flashing went.
Device Model CSC Version Bit OS Build date
SM-A715F / Galaxy A71 SM-A715F NEE A715FXXU3ATJ2 3 Q(Android 10) 20201020152334 (Now flashed into phone)
SM-A715F / Galaxy A71 SM-A715F NEE A715FXXU3ATI8 3 Q(Android 10) 20200930134804 (Odin3 firmware update via downloading works ok)
SM-A715F / Galaxy A71 SM-A715F NEE A715FXXU3ATH8 3 Q(Android 10) 20200831142334 (Odin3 firmware update via downloading works ok)
SM-A715F / Galaxy A71 SM-A715F NEE A715FXXU2ATG1 2 Q(Android 10) 20200701232104 (Fails..)
SM-A715F / Galaxy A71 SM-A715F NEE A715FXXU2ATE8 2 Q(Android 10) 20200519160329 (Fails..)
SM-A715F / Galaxy A71 SM-A715F NEE A715FXXU1ATA7 1 Q(Android 10) 20200115142416 (Fails..)
SM-A715F / Galaxy A71 SM-A715F NEE A715FXXU1ATA1 1 Q(Android 10) 20200103192741 (Fails..)
Odin3 fails with following info:
Here's log from Odin:
<ID:0/005> Odin engine v(ID:3.1401)..
<ID:0/005> File analysis..
<ID:0/005> Total Binary size: 8337 M
<ID:0/005> SetupConnection..
<ID:0/005> Initialzation..
<ID:0/005> Set PIT file..
<ID:0/005> DO NOT TURN OFF TARGET!!
<ID:0/005> Get PIT for mapping..
<ID:0/005> Firmware update start..
<ID:0/005> NAND Write Start!!
<ID:0/005> SingleDownload.
<ID:0/005> abl.elf
<ID:0/005> xbl.elf
<ID:0/005> FAIL! (Auth)
<ID:0/005>
<ID:0/005> Complete(Write) operation failed.
<OSM> All threads completed. (succeed 0 / failed 1)

I answer to myself
Is it possible to downgrade firmware from Bit 3 to Bit 1/2?
Is this Bit information saved into phone way that it cannot to be rewritten?
Click to expand...
Click to collapse
Bootloader version (BIT 3) cannot be downgraded, at least i didn't find any information about this. Any news?
TWRP lets you flash older firmware versions because it is ignoring bootloaders version check. There is no guarantee that older version of firmware works ok with newer bootloader. Needs to be tested.
New questions:
What happens if I take BL file from newer firmware and try to flash it with older AP, CP and CSC?

-JHS- said:
I answer to myself
Bootloader version (BIT 3) cannot be downgraded, at least i didn't find any information about this. Any news?
Click to expand...
Click to collapse
From what I know, no. You can't dowgrade bootloader version
-JHS- said:
New questions:
What happens if I take BL file from newer firmware and try to flash it with older AP, CP and CSC?
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Never tried it

ShaDisNX255 said:
From what I know, no. You can't dowgrade bootloader version
Never tried it
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What about creating custom "stock" rom? Latest NEE bootloader + rom from e.g. May. This procedure has been successfully used before, don't know if it works today.
https://forum.xda-developers.com/samsung-a-series/general/rom-t3614602
I have newer created any custom roms but I don't think it does not require nuclear power plant technology experiense So if anyone have, any updated guides for creating Custom ROM -> Please let me know (xda have so many of them, don't know which one to follow).
So working process could be following
* Flash NcX 2.5 A71 ROM with TWRP --> Getting TWRP for flashing
* Flash custom stock rom via twrp
* And yes, I get bloody MirrorLink working in A71
Please comment!

-JHS- said:
What about creating custom "stock" rom? Latest NEE bootloader + rom from e.g. May. This procedure has been successfully used before, don't know if it works today.
https://forum.xda-developers.com/samsung-a-series/general/rom-t3614602
I have newer created any custom roms but I don't think it does not require nuclear power plant technology experiense So if anyone have, any updated guides for creating Custom ROM -> Please let me know (xda have so many of them, don't know which one to follow).
So working process could be following
* Flash NcX 2.5 A71 ROM with TWRP --> Getting TWRP for flashing
* Flash custom stock rom via twrp
* And yes, I get bloody MirrorLink working in A71
Please comment!
Click to expand...
Click to collapse
Well, in theory it should be possible to leave your bootloader as is and just flash the new ROM with TWRP.
However, 2020 devices get a little more complicated because of what's called a super.img
Long story short, the only way I've tested to be able to work out a ROM would be with SuperR's kitchen
The Windows version is paid for and the Linux version is free, so if you don't want to invest money on the Windows version then use Linux version
The way to do it would be as follows:
-> Extract the firmware you want to make a ROM of with SuperR's kitchen
-> Use "sparse" type on everything
-> Make any changes you want to your ROM once extracted
-> Download the super image plugin
-> Use the kitchen to start building the following images:
->system.img
->vendor.img
->product.img
->odm.img
-> After all those are finally built (with "sparse"), then you can finally run the super.img plugin and start building a super img with those images inside it
-> After it's finally done, you can finally use that super.img and flash it with TWRP
So yes, it is a very tiring process. If this is really important to you and you really want to do this, contact me in Telegram (ShaDisNX255) and I can try to help you out.