values like 0x80 or 0x40 into a uint8_t foo:1 bitfield. This would
result in the bit always being 0. One of these caused a warning for
overflow (one that was 0x80), but the other didn't. They were both
wrong.
This is why I hate code that mixes c struct bitfields and #defines.
The rest of the fields accessed by the program should be audited.