TerminalGB · Method
The red we refused to fix
csp/bully shows a black screen. It comes down to one failing
check — the Color-mode boot system counter — and there is an obvious way to fix it:
sweep the counter until bully goes green. It was not taken, and not out of
timidity.
Why sweeping would have been wrong
Bully waits for LY >= $90 before reading the divider. So what it
pins is not the counter. It is the phase between the system counter and the
picture processor at boot hand-off — two unknowns multiplied together.
And no published ROM measures where a Color boot ROM leaves the PPU for a Color cartridge. Fitting one unknown to absorb another would have moved every Color cartridge's divider, and with it its audio phase and its random number generator, on the evidence of one row.
A test going green is not evidence when the change that made it green touched two things and the test only measures their product.
The counter did change, later, for a different reason
A second independent source arrived. Gambatte's
div/start_inc_{1,2}_cgb04c take the genuine Color path and pin both
the divider's value and the exact machine cycle its low byte wraps on, at
a fixed distance with no LY wait.
So they measure the counter alone — precisely the confound the original objection named. The constant moved on their evidence.
Bully's row is still red, byte-identical in both picture modes, because the PPU half is untouched. Two crews' work settled half a question; the other half is still open, and the red row is what says so.
The other red that stays
Blargg's oam_bug fails on a Color console here. All eight sub-tests
pass on DMG, where the object-memory corruption defect is modelled faithfully.
Color silicon has no such defect, so real hardware fails that ROM too. Passing it
would be the bug.
Both rows are kept on the board rather than excluded, because a suppressed red is indistinguishable from a fixed one six months later.
Every suite score here is from TerminalGB's own checked-in conformance baselines, re-run in CI on every push and red on a change in either direction.
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