HP Z240 will not boot when adding 4-port ETH card

[bearhntr]

I bought this machine refurbished and have upgraded the RAM to 64GB (booted just fine into the preloaded Windows 10 Pro after this installation.  I updated all the firmware and drivers which were needed using the HP Update tool.  No issues.  Booted many, many time with this configuration.  I then added a 4-port Ethernet card (HP 331T) which has been working for years in my old Dell Optiplex 7010 tower.  Never once had a problem with it there under Server 2016 and 2019.   The system will not boot.  I get a RED light at the power button flashing and 3-Slow beeps and then White light and 2-Fast beeps (i.e., 3.2 beep code).  It will repeat this 4 times and then just stop with solid red light.   There is no KB or VID at any point.  

I found that this error in the Maint Guide:

Hardware

3.2

The embedded controller has timed out waiting for BIOS to return from memory initialization. Indicates potential memory failure.

1 Reseat memory. 2 Correct memory configuration. 3 Test with known good memory. 4 Replace affected component.

I know that it is not the RAM -- system boots just fine if I take this card out.  I have tried BOTH of the slots that it will fit in.  Same issue in either.  I take the card out, put it back into the Optiplex 7010 and it boots right up-- all 4-ports are seen and usable.  I put the card into my HP T620+ which has a 2-port Ethernet card and runs pfSense.  The system boots right up sees the 4-port card and wants to re-configure pfSense to use the new MACs.  

I have tried everything.  I have used the CMOS button option -- does not help.  I have booted into the BIOS with the card removed and reset to Factory Settings - turned off every  single Security feature I can find and still will not boot with this card installed.  Boots just fine if I tale it out.  

There are some mentions in other forums that this card has an NVRAM on it - but I see no jumpers to reset it....how is this done?  How do I get this card to work in this HP Z240?  I want to build a Proxmox server, and this card is needed.  I know that Proxmox will use it, as I installed it on the Optiplex on a USB flash drive and was able to see it and configure it there.  

There has to be something stored on this card that is keeping the system from booting.  

I also found on another forum about covering pins B5 & B6 on the PCI connector.  I cut a small piece of electric tape and did this.  The system BOOTS JUST FINE with this done, but I am sure that those pins are used for something (SMBus is mentioned in the other article).  

I hope that some brilliant person know just how to fix this.  

[BeemerBiker]

This is a known problem and has shown up with other OPEM motherboards, not just this HP one.

Discussion with nice pictures is here

You can tape over the pins, grind the conductive off or use a different motherboard.

[bearhntr]

I did get it working by covering the B5 & B6 pins on the PCI board.  This is very strange, as I can put it into any other machine (2 of them are HP machines) and it does not have a problem.  I do not understand why the first time that I put into to the Z240 - it had no issues.  It booted up.  I was able to update the BIOS and drivers on the system using the HP Support Assistant.  Powered off the Z240 - took the card out to do some other testing (while I waited on the 64GB of RAM to arrive).  After that was installed and the card put back in - will not boot.

If you take the DIMM out of slot 1, and leave 2, 3 & 4 populated - the system will BOOT -- but only sees 32GB of the 48GB installed.