need help

i did the unexpected and accidentally upgraded firmware to ofw3.56
has anyone heard of a way to get it back to ofw3.55?
i have the original 60gb ps3 fat,,first one out ,anyway to get it back to 3.55 or earlier?
i have read that the originals had the large nand and firmware was stored on the chip as compared to the newer slims putting firmware on the hdd,,,does anyone know a way to downgrade this mistake?
thanks in advance

There is no way back at this time. By the way, firmware is always stored on a chip.

Cannot downgrade yet, and don't try using service mode or any lvl2diag. Currently, systems put into service mode on 3.56 are stuck in service mode till someone figures it out.