TX1 stuck in reset on custom carrier board after Nvidia TX1 SOM rev change

Using a Jetpack flashed TX1 SOM (Model: 21870 PN: 135-0657-000 R1 “B04”) plugged onto custom carrier (Carrier based off the B02 revision). After applying power to board, the board does not boot (complete lock, no serial console output). Instead the TX1 SOM reset line is held low ~0V indefinitely. Using the same Carrier Board but plugging a Jetpack flashed TX1 SOM (PN: 135-0601-000 R4 “B02”) and applying power to boot results in a successful boot. Reset is released and goes to ~1.8V and console output is normal as system boots Ubuntu.

This process was repeated on a Jetson Carrier (Also a B02 carrier) board which boots either of the flashed TX1 SOMs (B02 and B04). The RESET_OUT_L line was probed and found that it never drives high when using the B04 SOM on the Custom Carrier. RESET_OUT_L comes straight from the CVM connector that goes to the SOM, I have Ohm’d out the RESET_OUT_L line and confirmed there are no shorts to GND as it sees an open load on this net without the SOM plugged in.

I am thinking there is some input that the B04 SOM is waiting for before it will release RESET_OUT_L to 1.8V that was not in the B02 SOM. I have verified some of the more obvious signals ie: VDD_3V3_SYS_PG, 1V8_IO_PG, and VDD_5V0_[SYS,IO]_PG and all seem to be normal (high to their respective rail voltage levels). If we could possibly find out what interrupts/conditions are necessary for the B04 SOM to release RESET_OUT_L high, especially any that may have changed from B02, it would be greatly appreciated.

Since it is same as previous topics, please refer to https://devtalk.nvidia.com/default/topic/972030