I used flashrom on tinycore linux by PCEngines to flash apu4_v220.127.116.11.rom to my APU4C4 board.
These are the version numbers I get after updating the flash rom to v18.104.22.168:
PC Engines apu4
coreboot build 20190901
BIOS version v22.214.171.124
SeaBIOS (version rel-126.96.36.199-0-g393dc9c)
PC Engines apu2 setup v4.6.12
What I am wondering is that the setup menu says "apu2" setup v4.6.12.
Why would that identify as APU2 instead of APU4?