Question 5GHz WiFi & DFS Channels?

I have a One X running CM11. I noticed that it couldn't see my 5GHz WiFi signals at home whereas my two laptops can see them fine. After a bit of searching I discovered that there are various Android devices that have 5GHz radios but can't see any of the DFS channels (some information here). I therefore switched both my WiFi APs to static 5GHz channels, one to Channel 36 (5180GHz) and the other to Channel 48 (5240GHz) and now my One X can see them both.

It appears there are fixes for some devices but I can't find a fix for the One X. There is a file in /system/etc/wifi called 'TQS_D_1.7.ini' and another in /system/etc/wifi/ini_files called '128x_TQS_D_1.7.ini' that seem to contain some settings but I can't see anything that seems to suggest enabling or disabling 5GHz channels.

Has anyone else seen this and managed a fix or workaround? My workaround of using non-DFS channels is OK but I'd prefer it if I could allow the DFS channels.

Andy
HTC Endeavor (One X)
Android 4.4.2 - CyanogenMod 11