You can still follow pretty much the same instructions as in that post. There's a small difference now in how you do it.
You still need to add an access breakpoint like before. The code will now stop at two different places. It's the second place that you'll be interested in. The code will say:
ld c,E4
ld a,c
ld (ff00+47),a
Place the cursor at the ld c,E4 instruction and start typing (yes!) ld c,1a then pres enter. An assembler window will appear as you type. If you did it right, the code will now be saying
ld c,1A
ld a,c
ld (ff00+47),a
Disable the breakpoint in the access breakpoints window and reset the ROM (run, reset). If it works correctly, you may now go to file, fix checksums, and then finally save ROM as.