Touchscreen not working after building and flashing clean msm kernel for the Google Pixel blueline

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chiang...@gmail.com

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Mar 29, 2019, 10:26:25 AM3/29/19
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Hi

I have built and flashed clean AOSP.
fastboot flashall -w
Which worked like a charm.

Thn I build msm and flashed it with
fastboot boot Image.lz4-dtb

The phone reboots. But then I am not able to use the touch screen at all. I cant unlock the phones sim card. If I hold down the power button for a while and reboot it. The touch screen works. Not sure what causes that, but maybe the kernel has been removed and switched out with the old one?

Another similar question is. If Id like to put the Image.lz4-dtb file inside the AOSP ROM. Where should I put it, and is that possible? If that would make me able to flash both kernel and ROM at the same time?

Alessio Balsini

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Mar 29, 2019, 10:45:37 AM3/29/19
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Hi,

> The phone reboots. But then I am not able to use the touch screen at all. I cant unlock the phones sim card. If I hold down the power button for a while and reboot it. The touch screen works. Not sure what causes that, but maybe the kernel has been removed and switched out with the old one?

How did you build the kernel?
I suspect your device is missing the touch screen drivers (maybe the
drivers you have in your device are not compatible with your kernel).

`fastboot boot` just loads your boot image into ram, it does not flash
the boot partition. That's why the device switches back to the old
kernel after reboot.

> Another similar question is. If Id like to put the Image.lz4-dtb file inside the AOSP ROM. Where should I put it, and is that possible? If that would make me able to flash both kernel and ROM at the same time?

You should update the files in device/google/crosshatch-kernel and
then run `make bootimage`.

Cheers,
Alessio

chiang...@gmail.com

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Apr 1, 2019, 12:40:30 PM4/1/19
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I built the kernel using this guide https://source.android.com/setup/build/building-kernels

with the build/build.sh command

Do you have a tutorial for using the make bootimage command? Or should I just run the make bootimage command instead of the shell? And flash it in the same way

Thanks!

Alessio Balsini

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Apr 2, 2019, 4:49:06 AM4/2/19
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Here follows a possible approach. There are faster ways of achieving
the same result, but this is probably easier to explain :)

Copy the Image.lz4-dtb file you generated with build/build.sh to the
AOSP kernel folder of your device, substituting the existing one:

$ cp ${YOUR_KERNEL_REPO}/blueline/out/android-msm-bluecross-4.9/dist/Image.lz4-dtb
${ANDROID_BUILD_TOP}/device/google/crosshatch-kernel/

Go back to the AOSP folder and generate the boot.img that will contain
your kernel and write it to the device.

$ m bootimage
$ adb reboot bootloader
$ fastboot flash boot out/target/product/blueline/boot.img

Now your device has the updated kernel (you can check with `adbs shell
uname -a`), but outdated kernel modules (among which there is the
non-working touchscreen driver).
Remount the filesystem in R/W (by default is read-only at boot):

$ adb root
$ adb remount -R

`adb remount -R` will also disable verity (if not already disabled)
and reboot the device if required. If the device was rebooted, re-run
the previous commands.
Now it's time to push the updated kernel modules to the device:

$ adb push ${YOUR_KERNEL_REPO}/blueline/out/android-msm-bluecross-4.9/dist/*.ko
/vendor/lib/modules/

Reboot the device, now everything should work fine.

Cheers,
Alessio
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Chiang Lee

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Apr 2, 2019, 11:51:43 AM4/2/19
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Thank you!
This seemed to work :)
Had to run the adb disable-verity command before remounting.

I tried enabling dm-verity after pushing the .ko modules

It has resulted in "Your device is corrupt. It can't be trusted and may not work properly.
Visit this link on another device: g.co/ABH"

Pressing the power button to continue takes me into the bootloader for a few seconds, I see the Google logo for about 1sec. And Im back into the Fastboot Mode. I guess I can flash Pixel factory image. But how do I get pass the dm-verity check?

Thanks!

Alessio Balsini

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Apr 2, 2019, 5:23:04 PM4/2/19
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> Thank you!
> This seemed to work :)
> Had to run the adb disable-verity command before remounting.

That's strange, `adb remount` with -R should also disable verity.
Anyway, cool that it worked.

> I tried enabling dm-verity after pushing the .ko modules
>
> It has resulted in "Your device is corrupt. It can't be trusted and may not work properly.
> Visit this link on another device: g.co/ABH"
>
> Pressing the power button to continue takes me into the bootloader for a few seconds, I see the Google logo for about 1sec. And Im back into the Fastboot Mode. I guess I can flash Pixel factory image. But how do I get pass the dm-verity check?

That is an expected behavior, enforced for security reasons.
Unfortunately, being able to pass the verity checks would require to
update vendor.img, as well as the keys for all the verity checks, that
is not possible...

Regards,
Alessio

chiang...@gmail.com

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Apr 3, 2019, 9:42:31 AM4/3/19
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Thanks!

Hmm,

So it is not possible to flash custom ROM/kernels on the Google Pixel Device ending up with enabled dm-verity? Or is that for all Android Devices? Is it possible to flash custom rom/kernels without disabling dm-verity?

Raymond Wanyoike

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Jun 3, 2019, 9:49:53 AM6/3/19
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Hello,

Following the guide at https://source.android.com/setup/build/building-kernels for the Pixel 3 (blueline) will put you in the same situation; a bootable kernel, but without touchscreen (and I suspect other drivers, like audio) working:

$ repo init -u https://android.googlesource.com/kernel/manifest -b android-msm-crosshatch-4.9-pie-qpr2
$ repo sync
$ build/build.sh
$ adb reboot bootloader
$ fastboot boot out/dist/Image.lz4-dtb
$ # boots, but :(


> I suspect your device is missing the touch screen drivers (maybe the 
> drivers you have in your device are not compatible with your kernel). 

I find it odd that custom Pixel 3 kernels available on XDA (https://forum.xda-developers.com) boot and work (fastboot boot <kernel>) with stock vendor modules, but the kernels generated from the build guide requires workarounds to move things to /vendor/lib/modules.

Would this mean that the guide is broken for Pixel 3 (blueline), that the build/build.sh script is not suitable for building stock vendor compatible kernels?

Michael Burrows

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Jun 3, 2019, 9:50:24 AM6/3/19
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Thank you for helping me out a while back Alessio! I am now about to build the kernel again. Is there a way to implement the touchdriver(and maybe other drivers missing aswell) before building? To avoid having to do the steps you have provided me with? I know there are drivers I have to download before building AOSP. But I cannot seem to find any information about downloading drivers for the kernel.

Thank you once again

Alessio Balsini

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Jun 3, 2019, 10:31:22 AM6/3/19
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Not so easy... :) Drivers built for a given kernel may not be
compatible with a different kernel build due to ABI breakages.
As a result, in most of the cases (is ABI changed), old drivers must
be substituted with new ones to work.

Cheers,
Alessio
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Raymond Wanyoike

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Jun 3, 2019, 11:59:30 AM6/3/19
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OK; more troubleshooting. 😅 Compiled the blueline kernel; patched it with root (su); and booted it it up:

...
$ adb shell
$ su
# insmod /vendor/lib/modules/snd-soc-sdm845.ko
insmod: failed to load /vendor/lib/modules/snd-soc-sdm845.ko: Required key not available
# dmesg | tail -n3
[  507.155988] PMI: smblib_get_prop_dc_online: POWER_PATH_STATUS = 0x95
[  507.156461] healthd: battery l=88 v=4314 t=27.6 h=2 st=2 c=-494 fc=2956000 cc=65 chg=u
[  519.116179] PKCS#7 signature not signed with a trusted key


😅 signature not signed with a trusted key

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Alessio Balsini

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Jun 3, 2019, 12:38:54 PM6/3/19
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Wasn't that module already loaded by init?

-Alessio

Raymond Wanyoike

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Jun 3, 2019, 3:08:00 PM6/3/19
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I don't know; dmesg shows a bunch of errors in early boot:

# dmesg|grep PKCS#7
[    1.846059] PKCS#7 signature not signed with a trusted key
[    1.855653] PKCS#7 signature not signed with a trusted key
[    1.864403] PKCS#7 signature not signed with a trusted key
[    1.871683] PKCS#7 signature not signed with a trusted key
[    1.881490] PKCS#7 signature not signed with a trusted key
[    1.897577] PKCS#7 signature not signed with a trusted key
[    1.908881] PKCS#7 signature not signed with a trusted key
[    1.921134] PKCS#7 signature not signed with a trusted key
[    1.937646] PKCS#7 signature not signed with a trusted key
[    1.957838] PKCS#7 signature not signed with a trusted key


I tracked down the touchscreen module to /vendor/lib/modules/ftm5.ko

# insmod /vendor/lib/modules/ftm5.ko
insmod: failed to load /vendor/lib/modules/ftm5.ko: Required key not available

I'll keep digging...


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Людмила Салмина

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Jun 13, 2019, 12:28:01 PM6/13/19
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пн, 3 июн. 2019 г., 17:49 Raymond Wanyoike <raymond....@gmail.com>:
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Saurabh Sakhare

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Aug 9, 2019, 10:58:50 AM8/9/19
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On Friday, March 29, 2019 at 7:56:25 PM UTC+5:30, chiang...@gmail.com wrote:
Hi
I have a doubt. If i compile kernel with gcc. It boots up but touch screen is not working can I use AOSP gcc compiled modules.? 
 will it work?  

Alessio Balsini

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Aug 9, 2019, 12:39:37 PM8/9/19
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On Monday, June 3, 2019 at 12:08:00 PM UTC-7, Raymond Wanyoike wrote:
I don't know; dmesg shows a bunch of errors in early boot:

# dmesg|grep PKCS#7
[    1.846059] PKCS#7 signature not signed with a trusted key
[    1.855653] PKCS#7 signature not signed with a trusted key
[    1.864403] PKCS#7 signature not signed with a trusted key
[    1.871683] PKCS#7 signature not signed with a trusted key
[    1.881490] PKCS#7 signature not signed with a trusted key
[    1.897577] PKCS#7 signature not signed with a trusted key
[    1.908881] PKCS#7 signature not signed with a trusted key
[    1.921134] PKCS#7 signature not signed with a trusted key
[    1.937646] PKCS#7 signature not signed with a trusted key
[    1.957838] PKCS#7 signature not signed with a trusted key


I tracked down the touchscreen module to /vendor/lib/modules/ftm5.ko

# insmod /vendor/lib/modules/ftm5.ko
insmod: failed to load /vendor/lib/modules/ftm5.ko: Required key not available

I'll keep digging...

On Mon, Jun 3, 2019 at 7:38 PM 'Alessio Balsini' via Android Building <android-...@googlegroups.com> wrote:
Wasn't that module already loaded by init?

-Alessio


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Luca Porzio

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Oct 8, 2020, 11:48:15 AM10/8/20
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Hi,

Did anybody tried to overwrite the vendor modules by using Magisk remounting ?

Thanks,
   Luca

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