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Solved: Magisk 23.0 - Patching boot.img fails with "Process Error"

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timg11

Senior Member
Jul 20, 2010
187
19
I'm following the Magisk guide in this thread
My Pixel 3XL is running Android 10 - Build Number QP1A.190711.020.C3

My Pixel 3XL was under "Case II" you have the image.

Case II: You have access to the Fastboot-flashable image
A handful of OEMs like Google and Xiaomi provide Fastboot-flashable factory images for their devices. If you managed to grab such a package, then the raw ‘boot.img’ can easily be extracted from the archive.

I downloaded the factory image from Google as: crosshatch-qp1a.190711.020.c3-factory-59b11ce9.zip
Inside that ZIP there was another ZIP named: image-crosshatch-qp1a.190711.020.c3.zip
Inside that ZIP I found the file boot.img which I extracted and copied to the Pixel 3XL. The size is 65536 kbytes.

This file matches the structure and name of the example shown in the image in the thread.

I sideloaded Magisk-v23.0.apk and ran Install.
When Magisk 23.0 Installation patches this boot.img file, it reports:
Code:
-Device Platform: amr64-v8a
-Installing: 23.0 (23000)
!Installation Failed
!Process Error

At the top level of the outer ZIP file, there is also a file named "bootloader-crosshatch-b1c1-0.2-5672671.img" with size 8552 kbytes. Which is the correct boot image file to patch? That looks different, but possibly is the right one for the Pixel 3XL?

If I have the correct boot.img file, what other issues could cause this failure?
 
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timg11

Senior Member
Jul 20, 2010
187
19
I found the issue. With nothing substantial found in searches, and no responses, I figure it must be something unique in my configuration. After randomly trying things, it occurred to me that my directory name was long.
After we all got past OS filename length restrictions a couple decades ago, I now try to use descriptive names. I created a directory for the unpatched boot image in /storage/emulated/0/Download named "BootImageOriginal_crosshatch_QP1A.190711.020.C3"
So the full path to the image was "/storage/emulated/0/Download/BootImageOriginal_crosshatch_QP1A.190711.020.C3/boot.img"
Whether it is the length, use of underscores, or multiple "." characters, this was the issue.
By moving the file to /storage/emulated/0/Download/boot.img, Magisk was able to patch successfully and wrote the magisk_patched.....img file to the same directory.

I noticed the following messages at the end of magisk_install_log_....

Code:
cp: can't preserve ownership of 'busybox': Operation not permitted
cp: can't preserve ownership of 'magisk32': Operation not permitted
cp: can't preserve ownership of 'magisk64': Operation not permitted
cp: can't preserve ownership of 'magiskboot': Operation not permitted
cp: can't preserve ownership of 'magiskinit': Operation not permitted

Again, I don't find much when I search on these messages, so I guess they are a "normal" result, given the phone is not rooted at the time the patching occurs?

Edit - I completed the process with fastboot flash of the patched image, and after rebooting, Magisk is installed and working.

PS: I was wondering why it was recommended to use adb pull to copy the patched image, rather than just use the USB File Transfer function. I copied the file both ways, and a binary comparison indicates no differences, so use whichever you prefer.
 
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