This is a collection of various errors on the APU devices
On first boot - double characters on Welcome! screen
Scroll down three (3) times to Serial console options and tap Return.
Scroll down one (1) time to Install IPFire (serial) and tap Return.
The installation should proceed normally and without the double characters.
On first boot - Undefined video mode number
Loading vmlinuz...Loading vmlinuz... ok
Loading instroot..Loading instroot....ok
Probing EDD (edd=off to disable)... ok
Undefined video mode number: 317
Press <ENTER> to see video modes available, <SPACE> to continue, or wait 30 sec
When starting the APU for the very first time you may see the above error during the boot and before the installation of IPFire.
Start the process again by rebooting or reseting the device. During the new boot, follow the instructions above by scrolling to Serial console options. Do not click on Install IPFire 2.27 - Core 123 in the first screen.