I have a similar issue on similar hardware. Flight 6, Flight 7, Beta 2 and RC live CD lock up as soon as I start firefox on a machine that is currently running Dapper.
The trick is that the live CD tries running xorg at 24 bpp, which makes DRI fail to initialize and results in the lockups on dapper. Changing the default display depth (as I've done on the installed machine since Breezy) results in working DRI and no lockups (so far). Changing the display depth works on the live CD too.
I have a similar issue on similar hardware. Flight 6, Flight 7, Beta 2 and RC live CD lock up as soon as I start firefox on a machine that is currently running Dapper.
I have a Fujitsu Lifebook P2120
0000:00:14.0 VGA compatible controller: ATI Technologies Inc Radeon Mobility M6 LY
The trick is that the live CD tries running xorg at 24 bpp, which makes DRI fail to initialize and results in the lockups on dapper. Changing the default display depth (as I've done on the installed machine since Breezy) results in working DRI and no lockups (so far). Changing the display depth works on the live CD too.