Attached is the LMI Lambda keyboard's 8748 software, the LMI equivalent to CADR's "ukbd". This only matters to you if you have a LMI keyboard with its "brad board". If you have such a keyboard and your 8748 has bit-rotted, this will revive it. (The image is also being sent to bitsavers and such)
This was extracted from and compared between two separate working keyboards. I tested it by fully erasing and reprogramming an 8748, installing it into a keyboard, and plugging that directly into lambdadelta using an arduino as a level converter / UART. It works. I also documented the "unknown" double-bucky boot chord bytes while I was at it, so I have a complete map of the protocol now.
If you have a LMI keyboard that does not have the brad board, this may still be helpful. If you are in this situation, let me know. The brad board doesn't do much to the serial bits, it only inverts the serial polarity unless the 8748 is in reset. Most of the board is the speaker driver and 5V regulator.
I am still testing to confirm if the difference between LMI and CADR keyboards really is just the firmware; I will tell people later when a determination is made.