Had my Prusa i3 for a while, happily printing. Yesterday it started behaving odd, on an auto home it didn't return the Z to the correct place (about 2mm higher), checked the connectors, gave everything a blast with air in case any dust had got in & caused problems. It auto homed fine again. Today it is doing the same but even after checking connectors and an air blast it still isn't behaving. It does move up and down a bit.
On a different note I run Linux and during the last batch of updates the kernel was updated and now when I attach it via USB it isn't detecting it (via lsusb) so I've probably forgotten to change something but that isn't related to the above but might make it easier to diagnose
