Comment 1 for bug 1981637

I think this is expected - the snap declaration should use regex's for matching these attributes - something like the following I think (off the top of my head, this is untested):

"custom-device": {
 "allow-installation": [
      {
        "on-store": [
          "honeywell-international-inc"
        ],
        "slot-attributes": {
          "devices": "/dev/(mtd\\[0-9\\]|chunkfs/chunkfs\\[0-2\\])",
          "read-devices": "/dev/chunkfs/(geom|stats|sizes)"
        },
        "slot-names": [
          "fram-devices"
        ]
      }
    ]
}