Finally had time today to try again but no luck. This time I downloaded the 1.1 final release and tried installing it four times with no success. Just to check my ability to perform the install, I installed 1.0.6 and it booted successfully.
So since the start of this thread I have tried to install the 1.1 series release (rc2, rc3, final) ten times with zero success and the 1.0.6 release three times with 100% success. All of the installs were done using the "hold down left knob and switch" while powering on method (see https://forum.moddevices.com/t/mod-wont-boot-after-manual-install/712/12?u=jalbrecht for details)
I appreciate that there's nothing in the 1.1 series releases that should prevent boot up but I think you'll agree the install stats I've had suggest that's not the case. Any thoughts on a plan B would be greatly appreciated as I don't think there is any use in my trying to install 1.1 any more.
Would it be possible to get a 1.0.6 custom build with ssh password auth enabled? I'm more that happy to do any debugging on my end.