Comment 32 for bug 968759

You can keep the repository version installed and copy the downgraded version of libflashplayer.so to ~/.mozilla/plugins/libflashplayer.so to re-enable flash. I've found at least on my rig disabling Hardware Acceleration doesn't have much effect, nor does adding the line "EnableLinuxHWVideoDecode=0" to /etc/adobe/mms.cfg, but I took both of those actions, as well.