On Pixel 3a (sargo). I downgraded to Android 9 and tried to install from the ubports installer. But after flashing 3 files, the UI prompts me to select "Recovery Mode" and when I do, the phone just shows the Google splash screen with nothing happening.
This thread described this problem but is from years ago and it doesn't explain why this happened.
I also tried downloading the 3 files vbmeta.img, boot.img and dtbo.img and flashing them with fastboot. Same result when I try to boot into recovery after.
I can install Droidian by flashing, but it also doesn't give me a recovery.
I'm using slot b instead of slot a.