Hello!
So, i wanted to setup Freedombox on a Pi 3B+ and failed. i found this thread and thought i would help.
I checked the boot process of the Freedombox image and i triple checked that everything is fine (also booted Raspbian and read the serial console output which was fine).
I wrote the image with dd and Etcher. No matter what i do, i can’t get it booting and the Serial Output is garbled.
I have 2 Logfiles i created with Putty. A clean raspbian Buster boot and the garbled freedombox boot. I used a CH314A to read the serial console.
If you want the Logs let me know.