I've also received my Pinephone Pro and followed the same path that you did.
While I can't offer any guidance on getting Mobian bootable from eMMC yet, here's how I got my phone back to normal:
- Write SD card with Mobian (any supported distro should work)
- Press and hold the "RE" button on the back of the phone (cover removed), and the power button at the same time
After about 5 seconds, release the RE button. Keep holding the power button for another few seconds and then release - Mobian logo should appear
Now the eMMC has been bypassed and the phone is booted on SD
- Launch a terminal on the phone. If you run lsblk at this point, you should see both the eMMC and SD devices available.
- Download the Manjaro Pinephone Pro beta image and dd it to mmcblk2 which was eMMC in my case.
After rebooting, I have Manjaro installed on eMMC and Mobian on SD
While I can't offer any guidance on getting Mobian bootable from eMMC yet, here's how I got my phone back to normal:
- Write SD card with Mobian (any supported distro should work)
- Press and hold the "RE" button on the back of the phone (cover removed), and the power button at the same time
After about 5 seconds, release the RE button. Keep holding the power button for another few seconds and then release - Mobian logo should appear
Now the eMMC has been bypassed and the phone is booted on SD
- Launch a terminal on the phone. If you run lsblk at this point, you should see both the eMMC and SD devices available.
- Download the Manjaro Pinephone Pro beta image and dd it to mmcblk2 which was eMMC in my case.
After rebooting, I have Manjaro installed on eMMC and Mobian on SD