Hi,
the schematic looks good. Sorry I haven't noticed this thread earlier. I don't know what's your mainboard, but I had some problems with mine since EFI writes to flash during power up?/down? cycles and doesn't like hot switched chip during poweroff. Anyways, better be prepared to use external programmer, like „wiggler clone“ in case of everything fails.
Goodluck, Tadas (Mrtadis)