Dear Debian ~
Please forgive my neglecting to use the correct format for a bug report, but ~ let me explain. I am a 60 year old home Linux tinkerer, a Linux geek. I run Mint + Mate as my host and virtualbox, with a dozen guests. One guest is Debian sid. I just ran sudo apt update; sudo apt full-upgrade and got a black screen. I tried booting into fallback / recovery, and I got told the X-server had not started. Tried the old kernel, same deal. Small frustration ~ re-install. Chose the aarnet.edu.au mirror (I am in Brisbane) and booted, login as root, adduser mike sudo. Edit sources. Change the two lines that mention bullseye to read sid - delete everything else. Reboot. Black screen. Try the fallback - black screen. Try the recovery, ask for startx - same msg. I THINK your problem lays with the latest revision of the Xserver. If you would like a screenshot of the output in the tty when X wouldn't start, I have a screenshot I can send you. Reply to this email. I hope you find this helpful. Mike kneedragon1...@gmail.com