Amazing comment in the Copy ][+ source code:

#AppleII #retrocomputing

@a2_4am there were a couple versions of the RAMFactor firmware... Wonder if any of them fixed this. I might have to check.
@txgx42 please check! This is the only information I have about the buggy firmware.
@a2_4am I did a search through the available ROM binaries (versions 1.0, 1.1, 1.3, and 1.4) and didn't find anything that looks like 6502 code referencing either zp $19 or #$19
@txgx42 Interesting! Was this an 80s urban legend?
@txgx42 I found this snippet in the RAMFactor peripheral ROM while debugging something else in MAME. I wonder if "LDY #$19" used to be "LDY $19" in some earlier ROM version.
@txgx42 does not appear to be so in 1.0/1.1/1.3/1.4, never mind
@a2_4am Huh, interesting because I somehow did not even find that ldy when I was looking. Will have to take another look.