Is it possible to limit the bands/channels used on the 5Ghz on SSD40NBT?

There is no mechanism to selectively limit the channels in the 5GHz band for regulatory purposes, other than what is inherently supported in the module already (channel lists are defined by the country code in effect). The mechanism below is for end users to block connectivity on specific channels, but that is different from preventing transmission from a regulatory perspective. The 5GHzChanMask prevents the radio from connecting and scanning on certain channels in the 5GHz band. The setting is a simple bit mask with bit0 corresponding to channel 36, bit 1 is channel 40 and so forth. It gets a bit tricky as there are a few gaps. The below examples should make things clear. A value of 0×00071FF0 would allow the channels indicated below. 0×00071FF0 // {x,x,x,x, 52,56,60,64, 100,104,108,112, 116,x,x,x, 132,136,140,x, x,x,x} A value of 0×0078000F would allow the channels indicated below. 0×0078000F // {36,40,44,48, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,149, 153,157,161}