Although the crash seems to be dependent on the presence of the rt2500 module when in recovery mode, this is not the case when booting normally.
When booting normally, whether the rt2500 module is loaded or not, 'bouncing' the eth0 interface (whether from the GUI or the CLI) will lock the machine as previously described.
However, it does now appear that the ping/DHCP failure is connected somehow to running X, since that is what provokes that failure under recovery mode.
Worth noting as a further followup:
Although the crash seems to be dependent on the presence of the rt2500 module when in recovery mode, this is not the case when booting normally.
When booting normally, whether the rt2500 module is loaded or not, 'bouncing' the eth0 interface (whether from the GUI or the CLI) will lock the machine as previously described.
However, it does now appear that the ping/DHCP failure is connected somehow to running X, since that is what provokes that failure under recovery mode.