Owners who moved to nvidia-open 615.78.08 in October 2026 found that the CMP 170HX unlock installs without errors and the cards then go missing. The wiki flags it with a Warning, its badge for something that damaged hardware or lost data, and names 615.71.09 as the safe version.
What happens on 615.78.08
The cards fail to train PCIe Gen2 at boot and show up in lspci but not in nvidia-smi. Downgrading to 615.71.09 loaded the unlock on the first try, per @drew_2 (October 10, 2026).
@zagitta reported on October 17, 2026 that the boot loader (Booter) image changed in that release, and @scallion_9883 advised keeping the old booter. Installing v0.5 with ECC errored out on 615.78.08 and worked on 615.71.09, per @catchyuser and @.henrykrinkle (October 20, 2026).
The most serious report came on October 30, 2026. On Proxmox kernel 7.0.14-26-pve, with driver and kernel updated together, the cards failed at startup and the unlock retry path then corrupted host memory, per @galygious. A customized 615.78.08 build of their own later worked on all three cards, but it relies on a firmware workaround that is not public.
Which versions work
The installer accepts only the versions in its driver/VERSION file and refuses anything else. At master commit 2c7e2ec those are 615.78.08, 615.71.10, 615.71.09, 610.57.04, 610.43.03 and 610.43.02. Support for 615.78.08 was added to master on October 8, 2026, per @_j3ns, which is why it is on the list although every October field report on it failed.
615.71.09 was added in v0.4 and is the most widely confirmed working version, per @xeax (October 6, 2026). The 615 series works on the 10 GB card, per @68x0 (October 5, 2026). 610.57.04 is the older fallback; the Morrowmake fork's four-card P2P result was measured on it, per @trustinter (October 7, 2026).
Two edge cases. Inside a VM that also holds other NVIDIA GPUs, 615.71.09 plus cmpunlocker wedged those GPUs, so @darkmaniac7 (lab notes, October 21, 2026) ported the v0.5 core patches to 580.178.04. Older drivers such as 515 cannot be unlocked at all, because the exploit only works on 580 and newer, per @_j3ns (August 7, 2026).
How the wiki rates it
The Driver and unlock failures page marks the 615.78.08 failures Proven, meaning a second person reproduced them. The Unlock history lists the same episode as Contested, its badge for points where people disagree, and notes that the commit each reporter ran is not stated.
The practical advice is the same on every page: install 615.71.09, and keep a known-good copy to roll back to. The Troubleshooting table lists 615.78.08 as a usual cause when a card is in lspci but missing from nvidia-smi.