Could be your VGA, can you share your hardware config?
What was the LOGO like before you enter BIOS? Was it broken as well?
You can start with: clear CMOS, test with another cable, reseat your CPU and VGA
this is pretty common when you connecting PC to a TV monitor, try a regular smaller size monitor and see if it helps. You can change BIOS settings first with smaller monitor then connect back to TV monitor when in OS.
I'll try this, but sometimes the language changes to symbols with Chinese characters or something like that too. This new and old motherboard was the same model and it didn't happen on the same screen.