Now I've build crda for aarch64 ... and modify the rule that is added a ENV{COUNTRY}="DE", before RUN+="/usr/sbin/crda" but the rule isn#t done at any time and calling the crda on the command line leads to smartmeter:~ # COUNTRY=DE /usr/sbin/crda Failed to set regulatory domain: -7 can anyone explain how to get the physical available WLAN channel working? My fritrbox is using autochannel and is at channel 13 (and I guess that there is a reason for that due WLAN neighbourhood ... in past changing this had lead to trouble). smartmeter:~ # iw phy | grep MHz * 2412 MHz [1] (20.0 dBm) * 2417 MHz [2] (20.0 dBm) * 2422 MHz [3] (20.0 dBm) * 2427 MHz [4] (20.0 dBm) * 2432 MHz [5] (20.0 dBm) * 2437 MHz [6] (20.0 dBm) * 2442 MHz [7] (20.0 dBm) * 2447 MHz [8] (20.0 dBm) * 2452 MHz [9] (20.0 dBm) * 2457 MHz [10] (20.0 dBm) * 2462 MHz [11] (20.0 dBm) * 2467 MHz [12] (disabled) * 2472 MHz [13] (disabled) * 2484 MHz [14] (disabled) smartmeter:~ # iwlist wlan0 channel wlan0 11 channels in total; available frequencies : Channel 01 : 2.412 GHz Channel 02 : 2.417 GHz Channel 03 : 2.422 GHz Channel 04 : 2.427 GHz Channel 05 : 2.432 GHz Channel 06 : 2.437 GHz Channel 07 : 2.442 GHz Channel 08 : 2.447 GHz Channel 09 : 2.452 GHz Channel 10 : 2.457 GHz Channel 11 : 2.462 GHz smartmeter:~ # iw reg get global country DE: DFS-ETSI (2400 - 2483 @ 40), (N/A, 20), (N/A) (5150 - 5250 @ 80), (N/A, 23), (N/A), NO-OUTDOOR, AUTO-BW (5250 - 5350 @ 80), (N/A, 20), (0 ms), NO-OUTDOOR, DFS, AUTO-BW (5470 - 5725 @ 160), (N/A, 26), (0 ms), DFS (5725 - 5875 @ 80), (N/A, 13), (N/A) (57000 - 66000 @ 2160), (N/A, 40), (N/A)