As it seems, it taken some extra time, but a region free firmware came out for the DVR-A05 (105) of course unofficially! The patched firmware is the latest version (1.30) and as the "The Pioneer Region Free DVD firmware page" says "...2x and 4x speed selection for 1x media should be introduced later on...".

Click at the 'Source' link to download the patched firmware, at your OWN RISK!