I took the plunge on this last night:
I have some X9DRT-HIBFF nodes with onboard ConnectX3 (56Gb FDR Infiniband, but actually VPI).
X9DRT-HIBFF-2.10.0700.bin is the latest firmware available for those boards, which is so old as to basically make them worthless.
After doing some diffs on the firmware blobs between various versions of the X10 ConnectX3 boards and some other "sanity checks," I felt about 50% confident that I could successfully cross-flash the X10 ConnectX3 firmware onto the X9 board. This was still a pretty large risk, but I decided it was worth a try to make these more useful.
I cross flashed fw-ConnectX3-rel-2_42_5024-Super_Micro_X10DRT-HIBF-FlexBoot-3.4.753.bin onto my X9DRT-HIBFF node's ConnectX3, and it worked, and it automatically connected via VPI to Ethernet at 40Gbps on Linux after a reboot.
Anyway, I just wanted to leave this here for anyone wondering the same thing but afraid to try. Though don't sue me if you try some other untested variation than the one I posted above! Also, I'm not currently posting how to cross-flash here, as there are plenty of other searchable threads on this site already covering how to cross flash Mellanox firmware.
I have some X9DRT-HIBFF nodes with onboard ConnectX3 (56Gb FDR Infiniband, but actually VPI).
X9DRT-HIBFF-2.10.0700.bin is the latest firmware available for those boards, which is so old as to basically make them worthless.
After doing some diffs on the firmware blobs between various versions of the X10 ConnectX3 boards and some other "sanity checks," I felt about 50% confident that I could successfully cross-flash the X10 ConnectX3 firmware onto the X9 board. This was still a pretty large risk, but I decided it was worth a try to make these more useful.
I cross flashed fw-ConnectX3-rel-2_42_5024-Super_Micro_X10DRT-HIBF-FlexBoot-3.4.753.bin onto my X9DRT-HIBFF node's ConnectX3, and it worked, and it automatically connected via VPI to Ethernet at 40Gbps on Linux after a reboot.
Anyway, I just wanted to leave this here for anyone wondering the same thing but afraid to try. Though don't sue me if you try some other untested variation than the one I posted above! Also, I'm not currently posting how to cross-flash here, as there are plenty of other searchable threads on this site already covering how to cross flash Mellanox firmware.