I've seen threads on this issue but so far there's no actual solution, just a few posts from others having the same problems and some who don't.
ModNation Racers hangs while loading the first track (the screen with the controller layout visible) at 95% - after having chugged along for a long time at 5%. This has, according to others, been repeated with both the US and EU versions - I'm myself only trying with the EU version.
I've tested with everything from PSFreedom 1.1.1 and 1.1.2 to Hermes V3, V4b and PL3 V3 - and with both Open Manager 1.16, 1.17.1 and Gaia RC9 and RC10 to no avail. I've tested nodisc and with disc with all of these configurations, and I've (of course) verified my MRN backup to be error free.
Some of the times I've managed to hang the game at earlier stages in the boot process, but it's never gone further than 95%. I've tested exclusively from the internal drive.
The only thing I can think of that would cause this behaviour, and that would be consistent with it differing between users, would be some strange loading related issue where loading a backup from the hard drive is "too quick" and causes some internal game specific synchronization to fail.
Suggestions welcome - I've spent quite a few hours with this.