Hi Richard,
You could try to interrupt the boot sequence from a serial terminal, enter uBoot and tell the kernel to boot into single user mode, which prevents init from loading everything.
The following page might provide some help: http://donalmorrissey.blogspot.fr/2011/11/beagleboardd-ubuntu-1110-single-user.html
HTH
– JB.L
2012/6/29 H3llCaT <h3llcat69@gmail.com>