Weird error pattern on CC2541, the 8051 core
Trouble was what was returned was effectively always OR'ed with 1. Turns out the accumulator started internally at zero. When adding 1 at a time I would get: 1,3,3,5,5. Adding even numbers seemed to work but where actually offset by 1 (3,5,7,... instead of 2,4,6,...) due to the OR'ing-by- one issue.