Ok, connected my HD, opened two terminals, and then when the flasher was waiting at the dropbear prompt, I went to the second terminal (as root, in the directory above my initfs_flasher dir) and did:
I now have /mnt/initfs/dev/sda2 but I still can't boot to that partition. So now I need some guidance on workaround #2, the "simple sleep" command at the end of bootmenu.sh.

An interesting side effect: When I boot to internal flash or to an SD partition with the HD connected, my home screen comes up with the USB symbol in the tray and the drive already mounted. When I attempt to boot to the HD, and it fails and then boots to the internal flash, there's no USB symbol, nor is the HD attached (nothing showing under /dev)... An unplug-replug gets the drive online again... I wonder why? (EDIT: This is not the case, after all)