Wasn't sure what advantage the jpBear HBOOT would provide. I installed it and now I know: it restores the ability, for an s-off device, to execute Fastboot commands from the PC ! Nice. I temp-flashed AmonRa and did a Nand backup.
Next step: install CleanROM 4.5 Standard + GB Firmware patch.
Something I noticed about jpBear HBOOT... When I select the HBOOT option to reboot, the device doesn't reboot. It goes to sleep. I subsequently have to press the power button to get a reboot.