I've kept on playing with the CWWK X86 P5 with the 4x nvme hat and I've put a cable adapter on the e key wi-fi slot to plug one extra nvme to act as a boot drive, but it actually made a random nvme from the hat not recognized. Rebooting had the same effect on another drive. I wonder if the WiFi card slot is shared or exclusively somehow with the nvme hat.
There was also some difficulty on where to glue the adapter as the flat cable is not very flexible, so I kinda left it loose. But as the problem was not on that drive I've not considered it a problem.
There was also some difficulty on where to glue the adapter as the flat cable is not very flexible, so I kinda left it loose. But as the problem was not on that drive I've not considered it a problem.