Notes on Flashing a Harley Davidson TC265 ECU
Seed & Key Exchange appears to be static, with only one seed and key combination per ECU.
The Flash Memory read is done via service 0x23 readMemoryByAddress, after unlocking the controller and uploading a secondary bootloader, then activating it.
The Flash Write process uses service 0x34 requestDownload and service 0x36 transferData to write to the flash memory.