Hello! A few days ago, I succeeded to install ipfire 2.23 core 138 on a apu4c4. I had too problems with the video mode, because we are informed to choose the serial mode. But after installing the actual firmware with flashrom (which seems to be necessary to be able to read the actual image of IPFire), I found out that I had to put off the serial mode in the BIOS of the IPFire - and then everything went fine. May be this hint can help you in your case too. Have luck! Markus
I recognize this is an old post and you’ve probably already figured it out, but more documentation is helpful for the community.
I ran into this issue this morning and was halted for a bit as I couldn’t remember how I got past this last time I installed IPFire to my APU2D4. From the first boot page that comes up, select “Serial Console options”, then “Install IPFire (serial)”