and here is what strace sees wine sending out to the port:
write(13, "\33BT96\5", 6) = 6
write(13, "z", 1) = 1
write(13, "\33BT96\5", 6) = 6
write(13, "z", 1) = 1
write(13, "\33BT96\5", 6) = 6
write(13, "z", 1) = 1
...
I think the first line means " 1b 42 54 39 36 05 " in hex (confirmed).
And this can be found here in the update program
00073290 06 00 00 00 1b 42 54 39 36 05 00 00 ff ff ff ff |.....BT96.......|
000732a0 01 00 00 00 7a 00 00 00 01 00 00 00 ff ff ff ff |....z...........|
So, starting at 0x73294
if we also consider the next line, the z might be at 0x732a4.
The first number in the line corresponds to the number of bytes. Could be a coincidence, however.