Flashing the Cisco CX623106A NIC to OEM firmware

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New Member
Oct 9, 2020
I got only 9 and need 15 more in case someone is willing to sell them to me. Thanks!


Apr 27, 2022
Just for some confirmation, this does work. Was able to use a small jumper, boot the card and do the PSID change, power off then remove jumper, then power on and flash normally. Was able to convert all 20 cards from the Cisco flash to the fully-featured (with Crypto) Nvidia model MCX623106AC-CDA. Great guide! I had one freak out and start acting very strange in ESXi but the others have been great. Need to do some more troubleshooting whats going on.

The card acting up was the first card I tried to flash, and I ended up flashing it first to the non-crypto firmware, then changed it to the crypto and reflashed it. Not sure if that's what caused the weird behavior or what. Going to spend some time on it this weekend to see whats up. Basically the card is passing traffic from one port out the other when connected as redundant uplinks on a vDS in ESXi. This causes a massive network loop and brings the entire network to a halt eventually. Swapped out the card and it stops. I'm guessing something about messing with the firmware so much broke something with the hardware offload and its not doing what its supposed to.

Anyways, great guide, awesome that you found such a handy workaround!
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New Member
Jan 2, 2022
What am I doing wrong? I have a ConnectX-6 DX from eBay that spits out the following:

MST devices:


Soldered the jumper on and the card also burns constant orange and gets the following when updating:

flint -d mt530_pciconf0 --psid MT_0000000437 -i fw-ConnectX6Dx-rel-22_38_1900-MCX623106AS-CDA_Ax-UEFI-14.31.20-FlexBoot-3.7.201.signed.bin -ocr --nofs --allow_psid_change --yes burn

-W- Firmware flash cache access is enabled. Running in this mode may cause the firmware to hang.
-E- Cannot open Device: mt530_pciconf0. MFE_NO_FLASH_DETECTED