I believe you may be looking for the tricky process explained here:
http://tom61.arcadecontrols.com/axim_bootloader.html
I'm not trying to change the language, but I've recently experienced the "vanishing built-in storage" problem, and hard/soft resets don't bring it back. Dell is shipping me a replacement unit by tomorrow, but my original was bought this January and came with a PXA255. I'm afraid that the one they send me will be an older refurbished model with a PXA250 :(
So, tonight I plan to try the CF
boot loader procedure described at the link above. I figure I've got nothing to lose... but a question for y'all:
Let's say my Built-In Storage reappears tonight after I flash the device, and the unit they send me has a PXA250. Do you think I should keep my original unit, or does the Built-In Storage disappearance signal bad ROM and therefore future troubles?