Device Boot Loop Issue While Porting to Ubuntu Touch (Halium 13)

I am trying to port my device to Ubuntu Touch, using Halium 13. I have flashed the images to the right partitions, but I encountered a boot loop with the following behavior:

Boot Loop Sequence

1. The device shows the Motorola start-up logo for one second.
2. The device shows the unlocked bootloader warning screen for 6 seconds.
3. It shows the Motorola logo again for 6 to 10 seconds, but now with a horizontal pixelated line on the screen.
4. It then shows a blank screen for 5 to 10 seconds.
5. The cycle repeats, but the line gradually moves down on each reboot.

Troubleshooting Performed

At this stage, I entered the fastboot bootloader and tried:

fastboot boot twrp.img

However, the device immediately started boot looping.

I then replaced dtbo.img with the one from the latest LineageOS 20 build available for my device.

After this change, the horizontal line disappeared.

I was able to successfully boot TWRP using:

fastboot boot twrp.img

Logging Investigation

I attempted to read the pstore logs but couldn't find any useful output.

I suspected the kernel might not have been built with the required logging options enabled.

To address this, I:

• Created a separate logging.config file with the right kernel flags.
• Added it to deviceinfo.
• Verified that the options were correctly applied to the generated .config file located at:

workdir/downloads/KERNELOBJ

• Added the appropriate kernel command-line parameters to the vendor cmdline in the deviceinfo file.

Current Status

Despite these changes:

• The device still does not boot properly.
• USB does not become available.
• The pstore directory remains empty even after enabling all relevant logging flags and kernel parameters.

Source Tree

For debugging and error analysis, the device source tree is available at:

• https://gitlab.com/systemmaniac2010/motorola-rhode

Please help me out with this.