It turned out to be

but that worked like a charm. So for anyone else struggling with this and with a backup from somewhere between April and July that needs to clear their NVRAMs and get the phone back up (I'm afraid I may have a somewhat dodgy memory chip as well) or more generally, if you need to match up your backup with a corresponding kernel-power kernel, here's the (detail-free but succinct) pattern that worked for me , just read back in this thread a bit and substitute the kp version you require.

0. Have a backup-menu backup saved on your desktop
1. Reflash EMMC/FIASCO combined images, boot phone.
2. Add maemo-extras, maemo-extras-testing, maemo-extras-devel repositories back in
3. Allow update to 1.3
4. Install bash3, sudser.
5. Run the kernel-power command (see above) to install the next-to most recent kernel power kernel image
6. Reboot phone, put your backup images in ~/MyDocs/systemBackups/
7. Install backupmenu
8. Reboot into the backup menu (keyboard open) and restore your backup... huzzah! it works, no bootloop like if you have a mismatched kernel

Thanks for the help, you folks are the Maemo gods