Cheap OCP Mezzanine cards to standard PCIE


New Member
Jan 15, 2020
This thread is posted in order to pay back our fourms, beacuse the Inspiration comes from here. Will give us a new choice with Two port SFP+ 10GB Ethernet card,cheap and easy !

This thread tell you how to use a transfer suit to get a cheap 10GB Ethernet card,and a little work to change it
to brother model cx342a with two 10GB port!
1.use OCP to PCIE transfer suit Assembly with cx341a ocp card and put in windows or linux PC

2.OS will Recognized CX341A card with 1 Port 10GB,then we need change fw to cx342a at first.
Thanks to Mellanox,it's very easy to change fw in ConnectX-3!

Please allow me only post windows10 powershell Command,linux is basically the same.
Code: Mellanox drivers and tools,install it with default options
2.2 download file from  and decompress it to C:\Program Files\Mellanox\WinMFT,open poweshell  we will start it.
cd "C:\Program Files\Mellanox\WinMFT"
###check device info and record mac address
flint -d /dev/mst/mt4099_pci_cr0 q
###backup old flash,include fw and conf....
flint -d /dev/mst/mt4099_pci_cr0 rb 0 2097152 341a-cxen.bin
###write zero to flash
flint -d /dev/mst/mt4099_pciconf0 wb zero.bin 0
###write mellanox mcx342a fw to you ocp card,Notice XCC is work with hardware ver CX341A-XCAN to XCEN
flint -d /dev/mst/mt4099_pciconf0 --yes -i xcc.bin -mac f452149d2d14 --nofs b
#change mac address with before record‘s info,when flash done,you need reboot and will found two ports are Recognized by os,but is not Complete!

3 hardware change,you need Electronic welding tools
3.1 add sfp+ socket and shiled,is easy
3.2 use two 4.7uh inductance fill in pcb below c138 and c139, check the picture
3.3 use 1 yellow and 1green 0603 led fill in to pcb D4 and D2

ALL done,put it back to PC and check now CX342A is working now,iperf is used to check network performance test and stable test,you can use a scripts to start auto test and record result.
###PS C:\Program Files\Mellanox\WinMFT> .\mlxfwmanager.exe
Querying Mellanox devices firmware ...

Device #1:

Device Type: ConnectX3
Part Number: MCX342A-XCC_Ax
Description: ConnectX-3 EN NIC for OCP;10GbE;dual-port SFP+;PCIe3.0 x8;IPMI disabled;R6
PSID: MT_1680110023
PCI Device Name: mt4099_pci_cr0
Port1 MAC: f452149d2d14
Port2 MAC: f452149d2d15
Versions: Current Available
FW 2.42.5000 2.42.5000
FW (Running) 2.31.1602 N/A
PXE 3.4.0752 3.4.0752
UEFI 14.11.0045 14.11.0045

Status: Up to date
Last edited:


Feb 7, 2014
Wow. This is very cool. Great work!

I like that you still maintained the LP height.


New Member
Apr 29, 2020
Did anyone buy from taobao/1688?
I'd be interested into 2-5 adapter PCBs but ordering from those sites is just a hassle.
Otherwise I might just order PCBs from JLCPCB myself.


New Member
Sep 25, 2020
Count me in for a group buy from JLCPCB. I have a Chelsio 100g OCP card that I'd like to convert to PCIe.


New Member
Apr 29, 2020
The problem I found was that the OCP connectors are quite expensive, like 6€ per piece or so