Titanium: In flash is the bootloader and the ROM. The ROM you can change/update with a FlashSPI or softload if the OS is running.Do you know if you actually need a hard disc or sd card in it to load RISC OS? I'd kind of assume the entirety of RISC OS is in the flash chip so that it behaves equivalently to the old masked roms that it fitted on old acorn stuff. Point the PC at address 0 and hit go, and the whole thing comes up from there, no fancy bootloaders required.
A harddisc or a sd card you need only for the "harddisc stuff". You can open a rudimentary desktop without a external storage device but but does that make sense? Maybe for debugging.
For configure etc. you need a filcore device (same like Risc PC).
OMAP5 EVM or IGEPv5: Bootloader and ROM are placed on the SD card....