No boot after upgrade: vibration, red LED, then 2 vibrations and yellow LED

[3x5co]

I think the title says it all. I tried to upgrade from the CLI, and when I tried to reboot, the phone won't. Furthermore: I tried connecting to my computer, then turning on the phone with the volume up button help down. The LED turns blue, indicating it's in mass storage mode, but the computer doesn't see it.

Also, I flashed the most recent installer, and pre-built image, to SD cards, but them in the phone, and neither are seen by the phone.

[3x5co]

A semi-update: I learned from the tow-boot documentation that the Pinephone will not automatically load from an SD card unless you hold the volume button down while holding the power button. When I did this, I was able to boot from the installer SD. I'll leave this thread open in case someone has a specific solution to the issue of Mobian not booting. For my purposes, it was enough to re-install.