Max_Payload_Size is the value in the Max_Payload_Size field of the Device Control register. For a multi-function device whose Max_Payload_Size settings are identical across all functions, the common Max_Payload_Size setting must be used. For a multi-function device whose Max_Payload_Size settings are not identical across all functions, the selected Max_Payload_Size setting is implementation specific, but it’s recommended to use the smallest Max_Payload_Size setting across all functions.
Since some M/B BIOS doesnot field the right value on the Max_Payload_Size, that’s why we reduce the Max_Payload_Size size from 512 (Intel IOP348 default) to 256.
If you confirm that your hardware configuration works with older firmware version, you can downgrade the boot code back to original firmware to be able to use 512 payload size.Tags: ARC-1231Ml, BIOS, firmware