Whilst haven't done it for a while, can't remember any problems upon the last two occasions with two different phones. As in the UK if you want earpiece, microphone or vibrator just ask.

Have now disassembled another Jolla 1 and points to note:
1) Volume up/down button always falls out although obvious by slots in casing which is up and down.
2) When removing circuit board make sure that proximity sensor (black rectangle) comes out of housing as is a tight fit. There are two plastic lugs one on each side of circuit board, so need to prise board up at these points.
3) Note the way two connectors (by green barcode label) sit on top of each other before dis-assembling.
4) Antenna plug is probably most fiddly and easy to damage.
5) Two connectors by battery always fall flat and need lifting out of the way when reassembling.