Two results, one of which kills an operational hope I had been carrying.
THE RECORD IS MUCH BIGGER THAN I MEASURED. Reading 0x82175110 to the end: after
the two words, the 8-byte pair, the 184-byte memcpy and the 8 words at +200, it
copies 816 bytes at +232, 816 more at +1048, a sub-object at +1864 and a final
word at +1876. So the record spans +0..~+1880 = singleton +80..+1960, which means
word A is record +0 AND WORD B IS RECORD +1876. That retires last commit's "word
B has no known writer": there is no separate store because the whole record is
copied out, modified and assigned back as a unit (0x8216FF70 -> compare
0x822C3708, assign 0x82170650, then a worker 0x821700A8 -- note 168 decimal, not
hex, which I misread first time -- retrying a commit 0x822C33B8 up to five times).
IT IS NOT THE SAVEGAME, by two independent checks:
- size: every real save on disk is a 276-byte container deflating to 545 bytes;
the record is ~1880. It does not fit.
- files: after many sessions the content tree holds only game0N/savedata and
game0N/__thumbnail.png per slot plus three Headers/*.header. No second data
file exists anywhere under the title id.
Also negative: the savegame object is *(*(this+4)) + 304, and the singleton's
holder address 0x828F48B0 is referenced NOWHERE outside the accessor, so this+4
is a different holder -- the save block is not a window into this record.
=> Hand-editing a save cannot unlock the challenge missions. The earlier
savegame-editing win does not extend here.
WHAT WOULD WORK. The singleton is a static object at 0x828F4070 (0x8216F650:
addis 0x828F + addi 16496), so the gate words sit at fixed guest addresses with
no scanning: word A = 0x828F40C0, word B = 0x828F4814. Canary maps guest RAM into
/dev/shm and the project already reads it live, so writing 0xFFFF / 0x3F there
while the title sits on a menu should open all six challenge missions without
playing the campaign -- the route to the last 42 EX units. Untested; needs a run.