Happy 1050 OS

• BUG: The OS has a bug with the high-speed feature.  The bug is caused by the USD transmit routine stomping location $02/$0102 with 2*A for A = byte to be transmitted.  In normal circumstances, this is $82 because of transmitting $41 (ACK), but in at least one case, it's the previous byte at offset 1.  This explains how the corruption is deterministic across all the images.  The sector copier built into the Happy utility disk is safe, but will only read/write at ultraspeed to actual Happy drives.