There is no difference between the way a Naomi 1 and Naomi 2 interface with a NetDIMM board.
In fact, the same board can work on a Chihiro or first model of Triforce as well.
I have a DIMM board that is giving me the exact same error as yours, so I can give you a little insight as to how it happened to mine and what I have attempted to get it working again.
I was using mine for netbooting without a security PIC. Since I had grown weary of always having the connected PC running the python script, I decided to make a 0-key security PIC. Unfortunately, I have zero experience with PICs and haven't had a programming class since college ('88, and then the big language was Pascal). The net result is that I used the wrong type of PIC (a PIC16F84A-20/P instead of the correct PIC16F628A-I/P) and compiled the code with Microchip's PIC-18 compiler instead of a PIC-16 compiler.
I did successfully program the bad code on my incorrect PIC, though. When I loaded the PIC on my DIMM and powered it up it went directly to the ERROR 22. I figured that I had made a mistake somewhere and took it out but the ERROR 22 has persisted since then.
I have noticed that when I run the DIMM test in the test mode the firmware version is listed as 0.00. Is yours the same? My first thought was that the wrong PIC had erased the flash RAM BIOS, but that seemed pretty unlikely. Still, I had an extra BIOS chip from some earlier work and tried replacing it (the DIMM BIOS is on the lower board and is surface mounted, not for the feint of heart

). It is still reading version 0.00 with that one installed.
I got some advice from a SEGA technician who said that the ERROR 22 is most common when the SMD buffer chip 74LCX16245A on the bottom of the DIMM has failed. I replaced that, but still no joy.
If there is someone out there who has a better idea than those, they might be able to get us both going.
I have since gotten the correct PIC, programmed my own 0-key and replaced the DIMM board but it was a rather expensive learning curve.
Brian.