V9958 Missing Characters on Console

[roscopeco]

The standard V9958 console in the firmware (reported with both 1.2 and 1.3) occasionally misses characters when printing. This has been reported both as a standalone problem and with other issues (e.g. inability to load software via Kermit of SD card).

A recent occurrence of this issue looked as follows:

My current working hypothesis is that we have a race condition somewhere in the console's PUTCHAR routine. However, I still cannot rule anything else, including possible hardware issues, out at this point.