2. I'm not using U-boot correctly? Please note that I have no possibility to add/update items in U-boot. Whatever I do, it has to be from the U-boot console.
3. The card reader on the N900 is broken? That would mean USB is shaky at best and uSD broken. Sounds bricky to me.
Please somebody tell me I'm stupid and there is an obvious solution to this problem! Alternatively, is there any chance that U-boot 2012.04-1 has support for writing to the N900 rootfs? (just need to chmod +x a file, ability to patch (single bytes of) /sbin/preinit would be also enough for me to unbrick it. Is there any hope?