Author Topic: modified boot images lead to boot cycles  (Read 1402 times)

wobblykey

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modified boot images lead to boot cycles
« on: December 21, 2018, 04:51:29 pm »
Dear all,

for about two weeks I have been trying to install Lineage on the
Gemini but really got stuck.

So far I used the partitioning tool to select various combinations of
OSes. I mostly tried a rooted Android on the first partition,
downloaded all necessary files, unpacked and installed with the
flash-tool. It always works fine. I can boot all partitions.

The next step is trying to install TWRP into the recovery partition. As
a first step I install Magisk to give the TWRP app root
access. However, making Magisk modify the boot image always gets me
into a boot cycle which does not stop unless I boot into another
partition or flash everything from scratch.

Since Magisk can also be used without changing the boot image I use it
to simply give the TWRP app root and try to modify the recovery
partition so that I can boot into TWRP. Now I get into a boot cycle as
long as I boot into recovery. Booting the original rooted Android
works fine.

It seems that changing a boot image, no matter on which partition gets
me into a boot cycle: Device trying to boot, vibrate, going black,
trying to boot, ... and so on.

Does anyone have an idea how to get the TWRP boot image installed?
What is my mistake?

Thanks in advance and cheers,

   Thomas

Eldkatten

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modified boot images lead to boot cycles
« Reply #1 on: December 23, 2018, 05:03:34 am »
Hello wobblykey,

having no solution, I just want to add that I ran into the same problem (boot loop in recovery). I posted a question about it here, but never got a solution. So, I'm still interested in an explanation and a solution.

Just wanted to add some "weight" to your question.

Kind regards

rasva

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modified boot images lead to boot cycles
« Reply #2 on: December 23, 2018, 08:05:45 am »
Try to install TWRP using flash tool. It worked for me.
Cosmo
Gemini 4G/SailfishX

In past: Zaurus SL-C3200, Jornada 728, 690, Mobilepro 900C, Sharp PC3100, HP 200LX....

wobblykey

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modified boot images lead to boot cycles
« Reply #3 on: December 23, 2018, 10:05:09 am »
Quote from: rasva
Try to install TWRP using flash tool. It worked for me.

Tried that in the past already in various ways like using the flash-tool and even "dd if=./twrp.img" into the right partition in the adb shell, always getting into the boot cycle.

Just to make clear what I tried today again: copy twrp.img into recovery.img in the Gemini_x27_10122018 directory on my hard drive, use download in the flash tool => boot loop

I have the X27 model by the way and use linux on the desktop.

rasva

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modified boot images lead to boot cycles
« Reply #4 on: December 23, 2018, 11:18:29 am »
Quote from: wobblykey
Just to make clear what I tried today again: copy twrp.img into recovery.img in the Gemini_x27_10122018 directory on my hard drive, use download in the flash tool => boot loop

That is exactly what I did, only I use Win desktop for this. It works on my X27 Gemini. Just to make sure, do you have a correct version of TWRP? "Gemini" is also name of a completely different android device (some Xiaomi). I have this TWRP installed: https://forum.xda-developers.com/gemini-pda...-2-1-0-t3763855
Cosmo
Gemini 4G/SailfishX

In past: Zaurus SL-C3200, Jornada 728, 690, Mobilepro 900C, Sharp PC3100, HP 200LX....

wobblykey

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modified boot images lead to boot cycles
« Reply #5 on: December 23, 2018, 02:24:55 pm »
right, one needs to make sure to use the gemini-PDA version.

Just tried something else to trace the problem somehow. I extracted the working recovery.img from my recovery partition and did a hexdump which results in this output:

00000000  41 4e 44 52 4f 49 44 21  2d a4 7a 00 00 00 08 40  |ANDROID!-.z....@|
00000010  fb c0 3a 00 00 00 00 45  00 00 00 00 00 00 f0 40  |..:....E.......@|
00000020  00 00 00 44 00 08 00 00  00 00 00 00 29 09 04 0e  |...D........)...|
00000030  31 35 34 30 39 35 33 33  38 32 00 00 00 00 00 00  |1540953382......|
00000040  62 6f 6f 74 6f 70 74 3d  36 34 53 33 2c 33 32 4e  |bootopt=64S3,32N|
00000050  32 2c 36 34 4e 32 20 62  75 69 6c 64 76 61 72 69  |2,64N2 buildvari|
00000060  61 6e 74 3d 75 73 65 72  00 00 00 00 00 00 00 00  |ant=user........|
00000070  00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00  |................|


The twrp image results in the following output:


00000000  41 4e 44 52 4f 49 44 21  0b 0c 79 00 00 00 08 40  |ANDROID!..y....@|
00000010  83 17 71 00 00 00 00 45  00 00 00 00 00 80 f7 40  |..q....E.......@|
00000020  00 00 00 44 00 08 00 00  00 00 00 00 1a 11 04 0e  |...D............|
00000030  31 35 31 37 33 31 32 32  37 30 00 00 00 00 00 00  |1517312270......|
00000040  62 6f 6f 74 6f 70 74 3d  36 34 53 33 2c 33 32 4e  |bootopt=64S3,32N|
00000050  32 2c 36 34 4e 32 20 62  75 69 6c 64 76 61 72 69  |2,64N2 buildvari|
00000060  61 6e 74 3d 65 6e 67 00  00 00 00 00 00 00 00 00  |ant=eng.........|
00000070  00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00  |................|


Maybe one of the tech specialists can spot the problem. The most obvious to me was the difference in the bootvariant which is user or eng. Not sure whether this is relevant.

rasva

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modified boot images lead to boot cycles
« Reply #6 on: December 23, 2018, 03:20:42 pm »
Something about the build variants (eng, user) is here: http://blog.udinic.com/2014/06/04/aosp-par...build-variants/ but I do not think that is related to the problem you have.
« Last Edit: December 23, 2018, 03:21:18 pm by rasva »
Cosmo
Gemini 4G/SailfishX

In past: Zaurus SL-C3200, Jornada 728, 690, Mobilepro 900C, Sharp PC3100, HP 200LX....

rasva

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modified boot images lead to boot cycles
« Reply #7 on: December 24, 2018, 04:27:07 am »
Yesterday I noted something which can be related. I updated Magisk from 17.1.  to 18.0 and straigt after that was stuck in boot loop. Luckily I had backup, so I booted to TWRP and restored boot partition from backup. So, it may not only be problem with TWRP, but also incompatibility with somehing like Magisk which modifies boot image. After this experience I disabled update check in Magisk manager and will stay on 17.1.
Cosmo
Gemini 4G/SailfishX

In past: Zaurus SL-C3200, Jornada 728, 690, Mobilepro 900C, Sharp PC3100, HP 200LX....