Not able to erase MPC5566 internal flash through PE micro tool(the tool keeps on erasing and returns error in ONCE reg on abort), However we are able to erase and program SRAM. All connections and voltages are verified and found ok.
This could be issue of the tool in case of multibit ECC faults are created in flash memory.
Try using different debug tool like Lauterbach, iSystem,etc... for erasing of the flash memory.
I have encountered this in past on MPC56xx devices and more advanced debuggers were able to clear the ECC faults in flash memory.
Retrieving data ...