I recently got interested in the flashing processes of the older PowerPC-based ECUs, particularly, MED9.x. I noticed that these require both CAN and K-line connection when being flashed either via OBD or on the bench (with immo-off). This is somewhat unusual to me, I know that older ECU were flashed via K-Line, and newer ECUs are flashed via CAN. What does K-line connection do in the case of MED9.x? Gets it into special "Bosch service mode", transfers some external flash loader, or this is some strange kw1281 protocol where initiation happens over the k-line but the data gets transferred over the CAN bus?

thank you for your reply! you know, I have not personally encountered this. This is an impression based on reading some posts on this forum about flashing MED9 ECUs which might be incorrect. But it looks like the K-line is used, but only for the bench/boot.