Very interesting. This binary file is only 0x66000 (417,792) bytes long, whereas the file extracted from CH341a is full 0x200000 (2,097,152 or 2 MiB) bytes long.
Generally the Thunderbolt flash ROM contains firmware for two components:
- Thunderbolt (TBT) controller
- Power delivery (PD) controller
On this HP add-in-card, however, I don't see the power delivery firmware, so it must be on a different chip. This is most likely why the modified short file still works.
Note:
- The Thunderbolt flash ROM chip is 2 megabytes in size
- The firmware file you modified is only 408 kilobytes in side
- When you flashed the modified file using CH341a programmer, first the entire chip was erased. Then only the first 408 KB were written
- Normally this would kill the Power Delivery function, but you are lucky that PD firmware is most likely located somewhere else
Sure...please run
IORegistryExplorer and
scroll down to RP09, then post a screenshot.