Secure boot fuse programming

I’m trying to setup secure boot on ClearFog CX LX2 (lx2160a-cex7). Following NXP instructions for secure boot, I need to enable POVDD for fuse provisioning. In cex7 schematics, I can see that EN_SFP_PROG exists, but how can I enable it?

I already tried to blow OTPMK and SRKH writing SFP_INGR register with mw 0x01e80020 0x2 but the board reset and when I check the memory, OTPMK and SRKH are empty. Following the same instructions with NXP LX2160ARDB, I can enable POVDD when I put J9 to enable PROG_SFP, then I write the OTPMK and SRKH in the registers and I write SFP_INGR register, the NXP board doesn’t reset and when I check the memory after a manual reset, the OTPMK and SRKH were written correctly. Due that, I supose that the only different step is the POVDD enabled, so returning to the first question, how to do it (enable POVDD) in ClearFog CX LX2 (lx2160a-cex7) board?

If you have a Rev 2.1 of the LX2160a CEX7 module then enabling the PROG_SFP power circuit is done through GPIO1_DAT12, if the board is assembled with the proper assembly options. I am currently waiting to hear back from production if we are assembling this circuit by default or not. If it is a previous revision CEX7 module then the programming needs to be done through the GPIO exported to the carrier, but would also need hardware changes to enable this feature.

The simplified schematics for the LX2160A CEX7 2.1 only display the EN_SFP_PROG signal and its 1.8V/3.3V level shifter. Could you please provide information about the circuit that connects to the TA_PROG_SFP signal (pin G13 on LS1046A)? Also, for the PROG_SFP power circuit, could you share the part numbers or designators of the DNP components if this circuit is not assembled by default or if you cannot disclose the circuit itself?

I will update you once I have the answers from the hardware and production teams.

Hi. Are there any updates from them?