I think u-boot requires you to then run "u-boot-update-bootmenu", which will actually re-create the bootmenu.scr.

The best option would be to replace maemo's u-boot with a newer one directly on the NAND kernel partition. Should kill fremantle (its kernel), but should also allow u-boot to take whatever u-boot script is placed on the SD card, so on the long term, it's a better option.

I'm planning to do that, but I still have to find the b*lls to actually flash the newer u-boot (I know, it can be tested without flashing, but just need to get around to doing that..

Ref: https://leste.maemo.org/Nokia_N900