ok nothing has changed!OK so what should have happened is "XYZZY" should be displayed in the top left hand corner and then it is read back and displayed in HEX down and to the right.
Can you take a photo of your character generator ROM and for good measure checksum it to prove it is good, please? Replace once done! Re-run the CHARLIE test and check nothing has changed.
Interesting... so what it is meant to do is write XYZZY and then display 58 59 5B 5B 59 and we see 58 58 5B 5B 58 comparing the binary we conclude.. we lose the least significant bit is always being read as zero even when it should be set in the case of the Y character aka 59 aka 0101 1001 being read as 0101 1000. You've got (at least) one bit going missing on the way back!Ok this is DAVE config: