interesting thread. I had the other day what I did believe was a partially flashed firmware and bricked K-30, but which in fact was easily solved with a debug modset to clear and reset the system:
Bricked K-30 - PentaxForums.com
I bought a used K-5, which I am going to keep and sell the K-30. Initially wanted to flash the last firmware on the K-5, but after I read the misadventure of TomGarn I hesitate. SD cards have not the level of unreliability of the floppy disks of old computing days, but yet read/write failures and glitches are not so uncommon.
I guess I could do a flash only with a newly bought SD, formatted on the camera itself before transferring the file. It could be nice too if Pentax had checksums for their bin files, so check integrity after the file is on the SD, prior to processing. But then my K-5 seems to work nicely, and i don't use any of the latest nice shinny smart lenses, so no need to upgrade I guess.