I have a Nexus one and I have made a bit of a mess of it when loading a custom rom. Previously I'd rooted (without unlocking) the stock (2.2) rom before loading Cyanogen 6, later Cyanogen nightlies and finally eViL-NXSense-v1213. I was rather enjoying the last one but had severe stability issues which I think was due to using Titanium Backup and restoring data. I was in the process of re-imaging to eViL-NXSense-v1213 after clearing the SD card, data and various caches when something seemed to happen to the recovery image. I can get into the boot loader but if I select Recovery it shows the Nexus One logo indefinitely and doesn't respond to the power button being pressed, the same happens if I turn it on from cold.

Is it possible that the recovery image has somehow been corrupted? If so what can I do to restore a recovery image that will enable me to install a custom rom. I would prefer not to unlock the boot loader but will do it if necessary.