I can't get into the maintenance menu and also pressing D+M and doing a hard reset has no effect :-(
I'm sorry to tell you (to the best of my knowledge) that you have removed the diagnostic menus, bootloader and a 'small' linux system used to flash the unit.
You could have fixed mtdblock2 and mtdblock3 with the tools in mtdblock1 and mtdblock0. Without those tools you have two options; search for and try to use Jtag on your own to restore your unit, or send it to Sharp for repair.
I'm sorry I can't offer any more help.
Greg