@demise7625 I thought I bricked my pixel 2 xl until yesterday. I tried installing android 8 from flash.android.com since I read somewhere that it might help but it failed while flashing and the device was stuck on fastboot screen. I tried flashing android 9,10,11 after that but it kept failing. I gave up thinking I bricked the device. However, yesterday I managed to flash android 9 manually using a different computer (older). The only thing I did differently is I ran fastboot flashing unlock_critical this time. So either that helped or there was some problem with the computer.

After that I simply followed ubports installer instructions and everything worked seamlessly. So I would suggest try these, it might help:

1. Try fastboot flashing unlock_critical -> flash android 9 -> run ubports installer
2. Try a different computer and use a usb-a to usb-c cable.

I also remember reading that someone managed to get it work by using a usb dock insead of directly plugging into the laptop's usb port.

Sorry for the long answer, just logging my case hoping it might help someone in the futurej

@flohack yes I used calyxos before. Could that be the problem? I thought flashing stock undoes all changes from calyx. wouldn't it?

@mrt10001 I did try with those three options ticked that didn't help either.

@keneda yes I have selected the wipe option in installer but that didn't help. I have also tried wiping all partitions and formatting data to ext4 using twrp as suggested by @Flohack but that didn't help either. It always gets stuck at the mounting partitions step.

@abananaman @Flohack I am having the exact same issue. I have flashed android 9 (PQ3A.190801.002) using flash.android.com, made sure oem unlocking and usb debuggin are enabled on android 9. Installed ubports-installer (0.9.2-beta .deb package) and followed instructions. Now I am in ubports recovery screen on phone and the installer is stuck at mounting partitions...