@Izzy I put the contents of /proc/mtd in the pastebin too. Looks very much like /sdcard is just a subdirectory off another mount point? The results I cannot combine are that 1. with the HTC rom, the SD card was used (be it not optimally) e.g. for storing photos, so with the correct software the hardware should just work, but 2. in the recovery rom, the problem seems to be at the hardware level -- if only the SD card were recognised then mounting it should be -again- only a software issue.

@alle_meije I don't see the sdcard reported there anywhere, sorry. And without me being at my desk at home, checking and figuring is tricky at best. An SD card is a block device, so it should turn up in /dev/block. But from the output we gathered, only internal storage shows up (not even an internal sdcard).