OpenWRT/TravelMate/OpenVPN on an RP-WD009 Travel Router - 5GHz Issues

OpenWRT/TravelMate/OpenVPN on an RP-WD009 Travel Router - 5GHz Issues

I successfully installed OpenWRT 23.05.0, Travelmate, and OpenVPN on an RP-WD009 Travel Router. My home router (an Asus RT-AC66U B1 runing Fresh Tomato) and the RP-WD009 are both configured for country CA (Canada). My home router will transmit on 36, 44, 149, and 157 at 40MHz width - I suspect either the router hardware or the version of Fresh Tomato I am running does not allow me to broadcast on DFS channels 100-144.

OpenWRT can connect to my home router on channel 149 or 157, but not 36 and 44. The OpenWRT CA channels appear to be correct

root@OpenWrt:~# iw reg get
global
country CA: DFS-FCC
        (2402 - 2472 @ 40), (N/A, 30), (N/A)					36-48, single range @ 80MHz
        (5150 - 5250 @ 80), (N/A, 23), (N/A), NO-OUTDOOR, AUTO-BW		36-48, single range @ 80MHz
        (5250 - 5350 @ 80), (N/A, 24), (0 ms), DFS, AUTO-BW			52-64, single range @ 80MHz
        (5470 - 5600 @ 80), (N/A, 24), (0 ms), DFS				100-116, single range @ 80MHz
        (5650 - 5730 @ 80), (N/A, 24), (0 ms), DFS				132-144, single range @ 80MHz
        (5735 - 5835 @ 80), (N/A, 30), (N/A)					149-165, single range @ 80MHz

OpenWRT channels 36-64 show as disabled, 100-116 enabled, 120-128 disabled, 132-165 enabled, and 169-177 disabled.

root@OpenWrt:~# iw phy phy1 channels
Band 2:
        * 5180 MHz [36] (disabled)
        * 5200 MHz [40] (disabled)
        * 5220 MHz [44] (disabled)
        * 5240 MHz [48] (disabled)
        * 5260 MHz [52] (disabled)
        * 5280 MHz [56] (disabled)
        * 5300 MHz [60] (disabled)
        * 5320 MHz [64] (disabled)
        * 5500 MHz [100]
          Maximum TX power: 7.0 dBm
          Radar detection
          Channel widths: 20MHz HT40+ VHT80
          DFS state: usable (for 191 sec)
          DFS CAC time: 60000 ms
        (rest removed - working as expected)

The RP-WD009 appears to be using a MT7610E module that supports 5180-5825 MHz which should include the low channels.

root@OpenWrt:/tmp# iwinfo phy1 info
phy1      ESSID: 
          Access Point: 
          Mode: Client  Channel: 157 (5.785 GHz)  HT Mode: HT40
          Center Channel 1: 159 2: unknown
          Tx-Power: 11 dBm  Link Quality: unknown/70
          Signal: unknown  Noise: unknown
          Bit Rate: unknown
          Encryption: unknown
          Type: nl80211  HW Mode(s): 802.11ac/n
          Hardware: 14C3:7650 14C3:7650 [MediaTek MT7610E]
          TX power offset: none
          Frequency offset: none
          Supports VAPs: yes  PHY name: phy1

Any idea why the low OpenWRT channels are disabled? A quick check of logread and dmesg did not enlighten me.