Comment 4 for bug 543177

Till, I think your findings agree with mine (though I know nothing about using hplip to load the firmware, and I don't know how to confirm the firmware-corruption hypothesis), except possibly on one point in #2: It seems that if you turn the printer off and back on, the firmware will just be corrupted again, assuming the CUPS daemon is running. Were you implying otherwise?

I've done additional tests simulating the behavior of the hybrid backend with a Python script, and I've found that it's actually the usblp probe that introduces the problem. Without that, it's fine. This is strange because usblp is how it was done in the past, so what has actually changed? It could be changes in the hybrid backend, or changes in the usblp backend from previous versions of CUPS. Or my analysis could be wrong, of course.