Bootloop on Page after fastboot boot custom recovery.

[Anghirrim]

Ok, it worked after another try.

I was able to flash my recovery.img backup. It did solve the bootloop issue though.

To flash my complete 32Gb backup, should I just " edl.exe /w backup.img"?

[Renate]

Originally Posted by Anghirrim

To flash my complete 32Gb backup, should I just " edl.exe /w backup.img"?

NO!
Read and write are always used with respect to the device.
You just quoted a command that would write to your device.

This is how you make a backup.

edl.exe /r mybackup.img

[Anghirrim]

Originally Posted by Renate

NO!
Read and write are always used with respect to the device.
You just quoted a command that would write to your device.

This is how you make a backup.

edl.exe /r mybackup.img

Lol Ok, so here is what I have as backed-up files (see attachment).

Each individual files were backed up with:

.\edl.exe /r /pmypartitionname backupimagename.img

With the exception of my full 32Gb backup done with:

.\edl.exe /r 3.5.1_full_NAND_stock_backup.img

And when I just flashed back my recovery, I did the following:

.\edl.exe /w /precovery_a recovery-a.img

So what should I do to flash this full backup (knowing that my device has an eMMC), this?

.\edl.exe /w /s0 /c0 3.5.1_full_NAND_stock_backup.img

I guess no need for /m as eMMC is the default?

[Anghirrim]

Hmmmm, seems from what I can see on edl.exe /g, the active bootloader switched to slot b.

I think I have tried to send the slot change command through fastboot last Monday, but it remained stuck on "waiting for the device". Could it have somehow managed to change the active slot? Or it was the "fastboot boot customrecovery" that did it?

[Anghirrim]

Hi @Renate,

Sorry to bother you, but can you please just confirm how I should restore my backup with your edl utility? Here is what I found based on your website.

Should I go little by little, partition by partition like this:

.\edl.exe /w /ptargetpartition mypartitionbackup.img

Or should I go restoring full backup (knowing that my device has an eMMC), like this?

.\edl.exe /w /s0 /c0 3.5.1_full_NAND_stock_backup.img

Thanks in advance.

Note: I just called my backup a NAND backup by habit, but it's indeed the eMMC backup.

[Renate]

Just do the full backup/restore.
Bootloops can change many things.
It's just easier to restore clean.

I've been working on patching super and I've already had to full restore twice.
For me, this will do it all while I read my book on my old Poke3.

edl /lpoke5.bin /w /s0 /c0 poke5.img /z

With the /z it will reboot and I will hear it connect.

[Anghirrim]

Originally Posted by Renate

Just do the full backup/restore.
Bootloops can change many things.
It's just easier to restore clean.

Cool thanks! Yeah, otherwise I planned to make a full backup of the bootlooping device, extract it and compare img files md5sum one by one to identify the ones that changed... Painful perspective.

I'll keep you posted!

[Renate]

Originally Posted by Anghirrim

I planned to make a full backup of the bootlooping device, extract it and compare img files md5sum one by one to identify the ones that changed... Painful perspective.

Yes, it gets complicated quickly.

I wrote one byte to vbmeta_system_a and _b each.
It bricked. I compared using something that I had just written.
There was a ton of stuff that had changed, but ignoring userdata:

(null)                   0       784
uefisecapp_b      11649024      1712
persist           11651072     20139
persist           11659264     15714
persist           11661312      1216
persist           11665408      2262
persist           11669504      5111
persist           11681792         2
persist           11694080         1
persist           11698176         5
persist           11714560       532
metadata          11722752      2188
metadata          11739136         5
catecontentfv     12716032        20
uefivarstore      12718080        30
modemst1          12845056   1044028
modemst1          12847104    522280
modemst2          12849152   1043933
modemst2          12851200    522238
fsc               13107200        20
onyxconfig        13109248       715

The first column is the partition name.
The second is block number (quantized to 1MB or 2048 x 512 bytes).
The third is the number of bytes changed in that 1MB.

[Anghirrim]

Uhhhhh ok, I wouldn't have imagined this!!

So, HUGE thanks to you man!! Reflashing the complete backup saved my Boox Page. It's alive again.

You definitely deserve your wizard title!

I'll take some time to organize the notes and pictures I took to make a "Saving tutorial".

Thanks a million.

Now... I'll have to understand how and why it failed that much.

Thanks again!!

[Renate]

Oh! In my case I just had to switch the slot.
I restored the two bytes in the vbmeta_system_a & _b.

fastboot set_active a

And I got it all back without a full restore.

The hint for this was the modemst.
Apparently, they don't A/B that, just switch the contents.
Nope, this stuff is just rewritten all the time anyway.

So, my half-baked comparator did tell me something useful.

[Anghirrim]

Originally Posted by Renate

Oh! In my case I just had to switch the slot.
I restored the two bytes in the vbmeta_system_a & _b.

fastboot set_active a

And I got it all back without a full restore.

The hint for this was the modemst.
Apparently, they don't A/B that, just switch the contents.
Nope, this stuff is just rewritten all the time anyway.

So, my half-baked comparator did tell me something useful.

I indeed have modemst1 and modemst2. And long time ago I had rewritten to on a phone.

So lesson learned, instead of fastboot boot an image and have it loaded somewhere out of control, I'll flash the inactive slot recovery and switch between both.

[Anghirrim]

Well, kept trying to work on the recovery with adb activated.

I did as I explained before.
- Unpack recovery
- Modified the prop.default (attached) with:
ro.secure=0
ro.adb.secure=0
ro.allow.mock.location=0
- Repacked


When flashing the stock recovery on recovery_a, I can't boot into it. I just have a white screen with no adb, or nothing else.

However, force reboot works fine by pressing the power button.

What else can I do?

[Renate]

Originally Posted by Anghirrim

What else can I do?

I don't trust other people's tools.
I'm not saying that mine are more reliable, only that I understand them better.
Use imgutil.exe in my sig.

[Anghirrim]

Originally Posted by Renate

I don't trust other people's tools.
I'm not saying that mine are more reliable, only that I understand them better.
Use imgutil.exe in my sig.

Ok, I'll give it a try thanks.

I regularly use MagiskTools to repack the TWRP that I maintain for the Galaxy Tab S9 FE on XDA and it works fine.

I'll keep you posted.

[Anghirrim]

Originally Posted by Renate

I don't trust other people's tools.
I'm not saying that mine are more reliable, only that I understand them better.
Use imgutil.exe in my sig.

Ok, I did use your tool, it's really straightfoward. Quick one, the output recovery is now 45Mo large (instead of the original 100Mo).

Will it work with fastboot flash, or I'll have to go with edl (just asking because I don't want to mess-up the partition size on my device)?