You need to change your router's locale through SSH/Telnet to select these channels.
https://www.snbforums.com/threads/change-locale-settings.8012/
wl country EU
nvram set pci/1/1/ccode=EU
nvram set pci/2/1/ccode=EU
nvram set wl_country_code=EU
nvram set wl0_country_code=EU
nvram set wl1_country_code=EU
nvram set regulation_domain=EU
nvram set regulation_domain_5G=EU
nvram set wl_reg_mode=off
nvram set wl0_reg_mode=off
nvram set wl1_reg_mode=off
nvram commit
service restart_wireless
@eddiez:
Thank you for your quick reply! You have pointed me in the right direction.
I am sorry for my late reply: I did not want to try out your proposal, until I was a little bit more familiar with nvram modifications and the corresponding possibilities for an "undo"; this and the tests took some time.
I have tried several things, the most relevant ones are the following tests:
1) Application of the complete list of commands proposed by you (including "nvram commit" and "service restart_wireless") in a Telnet session. Even after several refreshes of the "Advanced_Wireless_Content.asp" webui page, the channels 120, 124 and 128 are still not present in the 5GHz-2 drop-down list. Result: no net effect.
2) Reverting back to the original settings (including "wl country: DE (E0/946) GERMANY" and "nvram get wl0_country_code: E0"). Application of the list of commands up to (and including) "nvram commit". After a refresh of the webui page, the channels 120, 124 and 128 did show up in the drop-down list. However after the command "service restart_wireless" and a refresh of the webui page, these channels were again no longer in the list. Result: only temporary success.
3) Reverting back to the original settings. Application of each command individually (e.g. "nvram set pci/1/1/ccode=EU", followed (in case of nvram values) by "nvram commit") and followed by a refresh of the webui page. Result: The only command sequence with an effect was "nvram set wl0_country_code=EU" + "nvram commit". After a refresh of the webui page, the channels 120, 124 and 128 did show up in the drop-down list.
4) Reverting back to the original settings. After the command sequence "nvram set wl0_country_code=EU" + "nvram commit", the channels 120, 124 and 128 did show up in the drop-down list. Channel "124" has been successfully selected, followed by pressing "Apply". After some refreshes of the webui page, the "Current Control Channel" was set to "124" , but the corresponding drop-down list selector was found in the position "Auto". The drop-down list does again not contain the three entries. Check with Telnet session: "nvram get wl0_country_code: E0" (thus the value reverted back to the original setting). Check of the activity of the 5GHz-2 channel: the SSID with channel 124 became visible (tested using a WLAN scanner) after some time (approx. 10+ minutes, long delay most probably due to DFS; for comparison: channel 60 in 5GHz-1 was available after approx. 1+ minutes), channel 124 was operating correctly (tested by successful connection of a WLAN client, with data traffic). Result: at least a temporary work-around.
Remark: I could not (yet) observe, whether the selected channel is "stable" in the long-term or whether it might get changed automatically as a consequence of the "Auto" position of the Control Channel selector.
I am just wondering, why the single nvram value, which showed an effect on the 5GHz-2 channel list, was "wl0_country_code" and not "wl1_country_code".
According to a post in the thread "RT-N66U, 5Ghz, rMBP problems" (16 Jun 2013):
wl0 is 2.4 GHz and wl1 is 5 GHz. wl is just a temporary value written by the webui, which then gets copied to ehtier wl0 or wl1, depending on which you were editing. [RMerlin]
Conclusion 1:
The following approach seems to be a current work-around: application of the command sequence "nvram set wl0_country_code=EU" + "nvram commit" in a Telnet session, refresh of the webui page, selection of e.g. channel 124 and pressing of the "Apply" button. The same procedure would have to be repeated for any new selection of one of the three channels and also in case of an automatic change (due to the "Auto" position) for bringing back the desired channel (e.g. 124).
It seems, that there is no (easy) way to make the nvram setting of "wl0_country_code" more permanent, i.e. that it survives the execution of the "service restart_wireless" command and/or a reboot. This observation is consistent with some information from other threads of this forum:
a)
Three posts in the thread "RT-N66U + Merlin can't update nvram settings" (17 Jun 2016):
- Starting with code level 376.xx or 378.xx (I can't remember which) you can no longer modify the wireless settings by changing nvram. [john9527]
- ... Those settings are hardcoded in the read-only bootloader, and the firmware directly gets those values directly from the bootloader now. [RMerlin]
- The limitation is in Asus's firmware, to comply with new regulations. [RMerlin]
b)
One post in the thread "nvram set and commit not holding" (21 Aug 2016):
- You cannot change region-related parameters, they are hardcoded by the firmware for legal reasons. [RMerlin]
In the meantime I temporarily reverted back to Asus' original firmware version 3.0.0.4.380.7266 (followed by a restore of "Factory default" router settings). The settings of "wl country" and of the NVRAM parameters (which are mentioned in the proposal of eddiez) were identical to those of Asuswrt-Merlin 380.65_2. Also with Asus' original firmware the channels 120, 124 and 128 are not present in the 5GHz-2 drop-down list.
Conclusion 2:
It seems that Asus would have to change their firmware in order to correct this issue.
