The restriction of the DFS channels needs to be done in the CLM_BLOB.
Also could you throw some insight as to how you are setting the freq_list using the wpa_supplicant.conf file?
I have only binary of the firmware and driver source. Could you please give me little details about CLM_BLOB.
You can set freq_list in wpa_supplicant.conf file in the network block.
psk="very secret passphrase"
freq_list= your comma separated allowed frequency list here.
You could refer to this application note to get more info about CLM.
Referring to the information from this link ,the frequencies in freq_list need to be separated by white spaces. Could you please check it?
Also if the frequencies are set using the freq_list, the scan results that do not match any of the specified frequencies are not considered when selecting a BSS.