yashsingh1/xdaforums huggingface dataset:
[Samsung Galaxy Tab A series Guides, News, & Discus] ebod:
yep something worth coming back to. Right now although I have an auto-boot, it boots twice, i.e. once and the battery animation flicks on...then a second later it boots again onwards into system. The next target is to kill boot loader unlock warning as it adds to the time during this double boot.

So cracking the process of getting this 'param' file is key
[Samsung Galaxy Tab A series Guides, News, & Discus] Talich52:
I decided to measure the boot time from the off state. Total 1 minute 20 seconds. The unlocked bootloader splash screen for the first 10 seconds, then the Samsung Galaxy Tab A splash screen for 40 seconds. If the unlock splash screen is removed, the total time will decrease by 10 seconds to 1 minute 10 seconds ... ;)
[Samsung Galaxy Tab A series Guides, News, & Discus] Minionguyjpro:
Using LineageOS 20, with the tweaked build.prop, and still having a unlock warning it'll boot in 20-30 seconds 😎!
[Samsung Galaxy Tab A series Guides, News, & Discus] Minionguyjpro:
Keeping it though, it works very nice. It has some exclusive features than from stock, also having a newer Android version. If LineageOS 21 releases for Android 14, I'll ask the developer from the official version to LineageOS 21, if it isn't yet from then. I saw that the version of LineageOS was first 19.1, as I saw a branch with it on the GitHub and also a LineageOS 20 branch.
[Samsung Galaxy Tab A series Guides, News, & Discus] ebod:
I've been exploring this logo action today and using the downloaded Samsung Theme creator tool I've managed to create what I 'hope' will be a Volvo looping image. Its set at 1280x800 and aimed to run in landscape on a car dash.

I've followed this old guide but its pics have long gone

https://xdaforums.com/t/how-to-create-your-own-qmg-boot-animations-must-be-rooted.2217795/

My final question just before I drop the modded bootsamsungloop.qmg into system/media ( I have made a backup! ) is about file permissions. What should they be using Root Explorer ?

A YT vid mentions '644' ?
[Samsung Galaxy Tab A series Guides, News, & Discus] Talich52:
My RootExplorer shows a different picture and a resolution of 0644.

And the general rule is that the new file must have the same permission as the old one.
[Samsung Galaxy Tab A series Guides, News, & Discus] ebod:
yey it did work without bricking the device ( rw-r-r- 0644 ). Only issue is its a squashed animation as I got the 1280x800 wrong, primarily I think it needed to be 800x1280 with the logo indexed round 90degrees to suit landscape viewing

But the method is proven, I just need to try again and once the animation loop file is correct...then do similar for the static boot/shutdown images.
[Samsung Galaxy Tab A series Guides, News, & Discus] Minionguyjpro:
And? Did you still do some stuff?
[Samsung Galaxy Tab A series Guides, News, & Discus] doniedogawa:
Hello, i just bought used T295 XID (indonesian version) with android 11 WC1 firmware and it's already bootloader unlocked. Can I install magisk without TWRP with this method?
[Samsung Galaxy Tab A series Guides, News, & Discus] Minionguyjpro:
Sadly, no, not anymore. Your bootloader version must be 3, which is 4. Version 4 does not allow ANY custom stuff anymore. The bootloader cannot be downgraded, for now.
[Samsung Galaxy Tab A series Guides, News, & Discus] doniedogawa:
So, I can't flash the OS back to 9 or 10?
[Samsung Galaxy Tab A series Guides, News, & Discus] J.Michael:
You can probably flash the OS back to 9 or 10. What you cannot do is reduce the version number of the bootloader.

I do not know whether flashing the version 3 bootloader (BL.tar file) results in successfully flashing and then having the tablet refuse to boot; or if the flashing phase results in failing to flash.

I am pretty sure people in this thread describe mixing and matching .tar files, i.e., they run Odin and specify an AP.tar from one release and a BL.tar from another -- that's how some people update Android to 10 without updating the bootloader past v3.
[Samsung Galaxy Tab A series Guides, News, & Discus] Minionguyjpro:
It might indeed be possible to lower the OS. I thought when you try to flash a lower bootloader, it just fails to flash it.
[Samsung Galaxy Tab A series Guides, News, & Discus] Talich52:
https://xdaforums.com/t/sm-t295-fin...d-19-march-2021.4050329/page-29#post-88120327
[Samsung Galaxy Tab A series Guides, News, & Discus] opmdzfwi:
Does this mean that once the tablet has updated to Bootloader 4, it is unrootable? Or just that TWRP cannot be installed?
[Samsung Galaxy Tab A series Guides, News, & Discus] J.Michael:
"Unrootable" is a deep philosophical question.

Once the bootloader has been updated too far, we believe you cannot flash unsigned software. That means no installing custom recovery (e.g., TWRP) or modified boot image.

There may be another way to "root", but I am not hopeful.
[Samsung Galaxy Tab A series Guides, News, & Discus] doniedogawa:
I tried to downgrade to android 10 with bootloader 3, and failed like this.

Okay, Talich52 is right. I have to give up for downgrading and rooting this tablet.
[Samsung Galaxy Tab A series Guides, News, & Discus] Minionguyjpro:
What if we try to use different software for flashing the older bootloader, like described in this video?
[Samsung Galaxy Tab A series Guides, News, & Discus] J.Michael:
By all means, try. But I don't think it will help. The software you run on the PC has nothing to do with it. It is one of bootloaders that is refusing to boot the next bootloader if it doesn't approve of the version number.
[Samsung Galaxy Tab A series Guides, News, & Discus] Minionguyjpro:
Could be, yeah. But my bootloader is still version 3, so do not want to risk it. And what about the EDL mode with flashing then? That could allows us to firce flash stuff.
[Samsung Galaxy Tab A series Guides, News, & Discus] J.Michael:
I'm confused. Are you saying you have a good, old, bootloader, but you're suggesting different flashing software on the PC for someone else to recover from a bad, new, bootloader?

My opinion is unchanged: What we call "the bootloader" is one of a sequence of bootloaders. The "rollback" is being prevented by either the on-device "flasher", or by the thing that needs to load-and-run the bootloader in the BL.tar. Either way, finding an alternative to Odin does not address the problem.

If what we use with Odin is not EDL mode, it's possible EDL mode would change things. I thought we still do not have what it takes to access/take advantage of EDL mode. Either we still don't have the Odin-like program that supports the protocol, or the images downloaded and flashed need to be signed.
[Samsung Galaxy Tab A series Guides, News, & Discus] Minionguyjpro:
Yes, I don't need change. But I have seen many people on bootloader version 4, asking to update it to support that which is not possible for now atleast. So I thought: what if we found out a way to roll it back forcefully in order to get back to bootloader version 3, which would allow flashing stuff again. EDL mode would allow to flash the bootloader, but there is need for a special file I thought and I honestly don't know how I would make it.
[Samsung Galaxy Tab A series Guides, News, & Discus] Minionguyjpro:
EVERYONE! Send an email to Samsung to tell about the bug in the bootloader with the vbmeta file or partition (I don't know how to call it). Just ask them to look into it. I heard this is a bug and we want it to be fixed. The problem we cannot flash anything off stock stuff is probably caused by this.
[Samsung Galaxy Tab A series Guides, News, & Discus] J.Michael:
I do not understand what you mean by "the bug in the bootloader with the vbmeta file or partition". This whole thread is about people successfully flashing modified software.
[Samsung Galaxy Tab A series Guides, News, & Discus] Minionguyjpro:
I mean with the new bootloaders, that's the thing that makes us being unable to flash things.
[Samsung Galaxy Tab A series Guides, News, & Discus] J.Michael:
You have a more christian attitude than do I. I have been assuming it is not a bug, but rather an expression of their continued efforts to stop people from modifying Samsung's devices. If anything, I thought Samsung considered the earlier ability to modify installed software to be the "bug" corrected by a later release.
[Samsung Galaxy Tab A series Guides, News, & Discus] shantz:
My device have Android 11

baseband : T295XXS6WG1

I want to install GSI or any old/new rom available, I have been trying to root it from past 2 days, as far as I understood there is no scope for rooting if your device is having higher versions. Can you please let me know if there is any other way to install GSI?
[Samsung Galaxy Tab A series Guides, News, & Discus] Talich52:
The device can be rooted only with version 3 of the bootloader. From version 6, it is impossible to downgrade even to 5, this is a ban by Google and Samsung.

I can't help you with GSI, because I don't use custom firmware and I have no experience with them...
[Samsung Galaxy Tab A series Guides, News, & Discus] J.Michael:
Rooting and installing a ROM are two separate things.

If you have a ROM packaged as tar files like the standard Samsung ROM, you can use Odin to install the new ROM. Then you have to contend with the protections built into firmware that is not affected by Odin. You might not be allowed to boot the new ROM.
[Samsung Galaxy Tab A series Guides, News, & Discus] Talich52:
Protection in the bootloader. Only the 3rd version of the loader allows you to install custom files, and the loaders 4;5;6 versions, being unlocked, still do not allow you to install any custom files:(
[Samsung Galaxy Tab A series Guides, News, & Discus] J.Michael:
What happens when you try to install an older bootloader?

Does the BL.tar fail to flash, but you can still boot, because you are still using a newer BL?

Or does the old BL get flashed, but then you are not able to boot, because the firmware that launches the BL refuses to run a lower version of BL than the highest version it has ever seen you use?
[Samsung Galaxy Tab A series Guides, News, & Discus] Talich52:
There will be a mistake. It is impossible to flash specifically the bootloader file aboot.mbn. That is, from 4;5;6, the loader version will not be lowered to 3. It is the loader who directs the filling of files, checking the signature and version, and he will not allow himself to be lowered in the version...

P.S. I have firmware T295XXS6CWG6 on my device, but with a bootloader of version 3. In the BL.tar file, 2 files about.mbn & vaultkeeper.mbn from android 9 have been replaced. And accordingly, the device is rooted :)
[Samsung Galaxy Tab A series Guides, News, & Discus] shantz:
Do you mean if I unpack the BL file and replace these two files will be able to root my device?

Shall I follow the exact procedure given at the start of the threat? Will I be able to install GSI or custom rom? I just want my device to be fast. Right now even if I open any application, it takes 10-15 seconds to load it.
[Samsung Galaxy Tab A series Guides, News, & Discus] Talich52:
This had to be done when upgrading the loader version from 3 to 4, that is, leaving the loader version 3 of android 9. And do so with each subsequent update. And now it's too late, the loader of the current version 6 and it can't be lowered :(

I can't say anything about installing GSI, but there are doubts that it will work with version 6 of the bootloader...

I recommend trying the firmware purely for Vietnam:

T295XXS6CWG4/T295OLB6CWG4/T295XXS6CWG2

It seemed faster to me :)
[Samsung Galaxy Tab A series Guides, News, & Discus] shantz:
Thank you so much for the reply @Talich52. As of now I think I will flash firmware again and try to remove bloatware. Let's see if there is any change in performance.
[Samsung Galaxy Tab A series Guides, News, & Discus] hkp935:
Hello there everyone,

Is there anyway i can install TWRP and on my sm-t295 with latest firmware (S6 bootloader)
[Samsung Galaxy Tab A series Guides, News, & Discus] XHYN_PH:
Only U4 Bootloader as I read... (Not sure)
[Samsung Galaxy Tab A series Guides, News, & Discus] J.Michael:
No.

@talich says version 3 is the last one that will allow patching.
[Samsung Galaxy Tab A series Guides, News, & Discus] Stage_PR23:
Aw it sucks to be in Bootloader 4. I hope there's a chance to have a tool that can revert back to BL 3 or lower but it dosen't so....

I installed CrDroid GSI on my tablet from an portuguese video about it and it seems it has root so I enabled it then I checked it via Root checker by joeykrim then I got root access. I don't know how it happened
[Samsung Galaxy Tab A series Guides, News, & Discus] Stage_PR23:
The problem is it does not have TWRP ofc it's bl 4 and I can't even have magisk module when I have supersu lol....
[Samsung Galaxy Tab A series Guides, News, & Discus] FERFAIL TXZ:
So, in summary, if you unlocked Bootloader in Ver 3, then you are fine. If you didn't, and updated to Ver 4, 5 or 6, then installing custom files or downgrading to Ver 3 is impossible... Right?
[Samsung Galaxy Tab A series Guides, News, & Discus] J.Michael:
Mostly right.

It doesn't matter whether you unlock the bootloader, if your bootloader is updated past version 3, you can not install custom software, and you cannot downgrade back to version 3.

Unlocking the bootloader in version 3 will not protect you against upgrading. You will need to be vigilant and never allow an update to change your bootloader.
[Samsung Galaxy Tab A series Guides, News, & Discus] Minionguyjpro:
Did anyone also test doing it with Heimdall? It will probably do the same but we need to know there.
[Samsung Galaxy Tab A series Guides, News, & Discus] J.Michael:
Heimdall and Odin just pour data into the line, it's the software on the device that decides what to do with it. Since there are reports of the device bootlooping, I think you are free to write anything you want to the device, it gets written to the partition. (Except for the parts under Rollback Protection -- I think those don't get written, or it would be no problem to revert to an earlier version of the bootloader.) Then, when you try to boot, the bootloader refuses to run it if the bootloader is not satisfied with the signatures.
[Samsung Galaxy Tab A series Guides, News, & Discus] Tianhe:
Current State: SM-T295 running on XXS3ATB2 stock with BL unlocked on factory settings.

KG Status: Checking

Samsung Binary: Official

1) The entire XXS3ATB2 AP.tar.md5 file has been patched on phone with latest Magisk Manager as well as Canary Magisk Manager. Used ADB to push/pull the stock/modified TAR file.

2) Odin flash error: On flashing the self magisk modified AP.tar with Odin3_v3.14.1 / Odin3_v3.14.1_3B_PatcheD version (with all relevant files), VBMeta Secure check fails, Odin says flashing failed and phone auto-reboots even though auto-reboot is unticked (surprisingly a failed flash doesn't corrupt the phone !).

3) After auto reboot i interrupt the process on UBL warning screen and force it to downloader mode. Then force reboot to stock recovery and wipe data.

4) Thereafter again force reboot to recovery and then use boot to system option.

5) On boot, Magisk Manager is not present hence i install it. After install it indicates that Magisk is not installed and i am back to square one.

6) I believe i have attempted more than two dozen flashes with various combinations and all end with failure.

7) Even ported a TWRP recovery build but that too fails (most probably due to my incompetency rather than flashing error)

Questions:

1) By [MENTION=1826556]gcrutchr[/MENTION] 's magic - you mean editing the boot.img & recovery.img file with hex neo editor ? Could you elaborate on that point ?

2) [MENTION=4470081]topjohnwu[/MENTION] had noted that an incorrect "header_size" field in the boot image header will trigger vbmeta error and refuse to boot even if the device is unlocked. Is this what i am facing on this phone? (By his own admission Samsung Pie SAR A-only devices launched in or after 2019 are the worst phones for patching)

2) Is it possible to create a custom signed vbmeta.img?

Cant roll back to previous firmware since BL V3 > V2. Android 10 for this device is due in August 2020, not sure whether that's a good or bad thing. And thank you for hearing me out patiently :)
[Samsung Galaxy Tab A series Guides, News, & Discus] J.Michael:
I settled on Canary debug build and 3B's patched Odin. I'm not sure it mattered. At any rate, the Canary debug you download today won't be the one I used.

I remember the reboot-in-spite-of-unchecking-autoreboot. It had me hovering over the tablet to try to intercept it. I think on my "successful" flashes (meaning I was happy with the result), it did not reboot until I pressed buttons.

I'm not sure the Odin error is a deal breaker. You'll have to compare the files listed in Odin to see if it looks like all files were downloaded.

If the tablet currently boots, I think you should try flashing the tiny tar (plus 3 stock files). I expect Odin to pass, and tablet to complain. Try to get from download screen to recovery to wipe data.

(I don't understand why you talk about interrupting the auto-reboot and going to download mode again before getting to recovery. I think it was always as easy to get to recovery, assuming I was able to interrupt the reboot.)

I don't understand going to recovery to reboot to system. I would shut down. Then boot, holding buttons to boot to recovery. But let go of buttons at first sign of life -- any screen that says Samsung, let go and wait. You don't want to get to recovery. If you do, shut down and try again. (This is the step I said you should try at least a dozen times. "Dozen" is just the word I chose for "stubbornly keep trying, hoping this time will be different, with no way to tell whether you are wasting your time".)

If, after booting, setting up (including wireless connection), and maybe installing Magisk Manager, Magisk Manager just comes up, without saying it needs to do other stuff, shut down and try again to boot towards, but not to, recovery. At least you won't have to answer the setup questions every time.

Re: [MENTION=1826556]gcrutchr[/MENTION] 's magic: Yes, I meant the step of taking boot.img and recovery.img from magisk_patched.tar and padding each of them with the tail end of the corresponding file from the original, stock, AP file.

I don't remember the talk about the header_size field in the boot image header. Maybe he was explaining why he modifies boot.img when Magisk is being jammed into recovery.img. That might also be why he emphasizes that you must not flash just recovery, but instead should always have at least 3 files (boot, recovery, vbmeta) in the tar file in the AP slot.
[Samsung Galaxy Tab A series Guides, News, & Discus] Tianhe:
Ok. Some progress, some not so..

1) First things first, this is the "hardware combo button dance" i need to do to get to recovery in normal circumstances when TAB is booted and running (this will be important later):

i) Restart Tab with Power + Vol Up combo.

ii) Upon restart, TAB briefly flashes "Samsung Galaxy Tab A" logo. Immediately release the entire button combo.

iii) Bootloader UL warning screen appears for some time. Do nothing. (If you press power key, it continues boot-to-system. If you press Vol+ or Vol-, it takes you to boot options - Power Off/Restart/Recovery/Fastboot/Back to previous page. Recovery option takes you to bootloader, Fastboot is meaningless and just restarts the TAB & Back to previous page goes to UBL warning).

iv) After approximately 3-5 seconds, the UBL warning screen disappears and the "Samsung Galaxy Tab A" screen logo reappears - Immediately press Volume+ button and do not release it until it goes to recovery screen.

v) Desired Recovery mode appears for wiping data etc.

2) Now, the good news. Odin successfully managed to flash patched AP file (stock AP file modified with [MENTION=1826556]gcrutchr[/MENTION] 's patched boot/recovery/vbmeta; mine may be corrupted during hex editing). Surprisingly, normal stock FW flash takes more than 5 minutes whereas modified AP file with BL, CP, HOME_CSC takes less than 30 seconds to flash successfully. No vbmeta error too.

3) Then "Try to get from download screen to recovery to wipe data". Following the "hardware combo button dance" procedure at point no.1, i reach 1-iii (UBL warning screen appears). Thereafter, when "Samsung Galaxy Tab A" screen logo reappears, i Immediately press Volume+ button so that i can go directly to stock recovery for wiping data.

4)

This is where things get interesting

- Instead of the expected recovery mode, i am greeted with an android on blue background with the words "erasing" (pic attached). Before i can do anything else, the TAB reboots. I can then get to recovery mode via point no. 1-iv and wipe data.

5) After wiping data from recovery, i boot directly to system but Magisk is missing. Re-installed Magisk Manager but it shows Magisk 20.4 as not installed and i am back to where i started from.

Now, i suspect that the forced "erase" has something to do with this entire fiasco. Still trying different combinations to see what sticks.....
[Samsung Galaxy Tab A series Guides, News, & Discus] J.Michael:
Did you flash a full AP file, with 8 or 12 files in it? Or a small AP file, with just 3, patched, files in it?

I don't understand how Odin can download any faster if it has the same amount to download.
[Samsung Galaxy Tab A series Guides, News, & Discus] Tianhe:
1) Flashed BL, CP, Home_CSC with full modified AP file containing 08 files: meta-data (folder), boot.img, dtbo.img.lz4, recovery.img, system.img.ext4.lz4, userdata.img.ext4.lz4, vbmeta.img & vendor.img.ext4.lz4 and ODIN shows Pass after about 25 seconds.

2) I do not flash the small AP file only coz it fails in Odin.

3) My best guess is that Odin probably checks and skips the partitions which do not need modification overwrite. Unfortunately, ODIN doesn't provide text logs. However, here is the process log of ODIN flash (Note: I have renamed the modified AP file as Compiled_AP.tar)

<ID:0/006> 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..
<OSM> Enter CS for MD5..
<OSM> Check MD5.. Do not unplug the cable..
<OSM> Please wait..
<OSM> Checking MD5 finished Sucessfully..
<OSM> Leave CS..
<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:0/006> Odin engine v(ID:3.1401)..
<ID:0/006> File analysis..
<ID:0/006> skip file list for home binary
<ID:0/006> bksecapp.mbn
<ID:0/006> Compiled AP/
<ID:0/006> Compiled AP/boot.img
<ID:0/006> Compiled AP/dtbo.img
<ID:0/006> Compiled AP/recovery.img
<ID:0/006> Compiled AP/system.img.ext4
<ID:0/006> Compiled AP/userdata.img.ext4
<ID:0/006> Compiled AP/vbmeta.img
<ID:0/006> Compiled AP/vendor.img.ext4
<ID:0/006> Home Binary Download
<ID:0/006> Total Binary size: 300 M
<ID:0/006> SetupConnection..
<ID:0/006> Initialzation..
<ID:0/006> Get PIT for mapping..
<ID:0/006> Firmware update start..
<ID:0/006> NAND Write Start!!
<ID:0/006> SingleDownload.
<ID:0/006> aboot.mbn
<ID:0/006> sbl1.mbn
<ID:0/006> rpm.mbn
<ID:0/006> tz.mbn
<ID:0/006> devcfg.mbn
<ID:0/006> cmnlib_30.mbn
<ID:0/006> cmnlib64_30.mbn
<ID:0/006> km4.mbn
<ID:0/006> apdp.mbn
<ID:0/006> msadp.mbn
<ID:0/006> NON-HLOS.bin
<ID:0/006> sec.dat
<ID:0/006> mdtp.mbn
<ID:0/006> adspso.bin
<ID:0/006> vaultkeeper.mbn
<ID:0/006> modem.bin
<ID:0/006> cache.img.ext4
<ID:0/006> product.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)
[Samsung Galaxy Tab A series Guides, News, & Discus] gcrutchr:
I had same problem. No root. Read Magisk website for key combo:

After installing Magisk:

(Powering up normally) → (System with NO Magisk)

(OEM Recovery Key Combo) → (Splash screen) → (Release all buttons) → (System with Magisk)

(OEM Recovery Key Combo) → (Splash screen) → (Keep pressing volume up) → (Actual recovery)
[Samsung Galaxy Tab A series Guides, News, & Discus] gcrutchr:
Now I have root!