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fix(openwrt): move 5GHz off DFS ch100 to non-DFS ch149/HE40 #106

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kblack0610 merged 1 commit from fix/openwrt-5ghz-non-dfs-ch149 into master 2026-07-09 03:17:21 +00:00
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kblack0610 commented 2026-07-09 03:17:12 +00:00
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What

Move 5GHz from DFS ch100 to non-DFS ch149/HE40.

Why

Regression from PR #100. ch100 is DFS; on this AP (ASUS TUF-AX6000, MediaTek MT7986/mt76) the DFS bring-up wedges hostapd on boot - after a reboot hostapd hangs in D state, phy1 shows NOHT with no beacon, and 5GHz (BrownLightning) never comes up while 2.4GHz is fine. Confirmed live: recovered with wifi up radio1. This recurs on every reboot while on a DFS channel.

Fix

Root-cause fix, not a watchdog: non-DFS ch149/HE40 has no radar CAC, so 5GHz comes up instantly and survives reboots. 149/153 is ~6 neighbor APs by scan, still well off the congested 36-48 block. Trades HE80 width for reboot-safety.

Verify (post-merge)

  • iwinfo phy1-ap0 info -> Channel 149, HT Mode HE40
  • logread shows a normal bringup with NO DFS-CAC-START line
  • 5GHz clients reconnect; hostapd in S state
## What Move 5GHz from DFS ch100 to non-DFS ch149/HE40. ## Why Regression from PR #100. ch100 is DFS; on this AP (ASUS TUF-AX6000, MediaTek MT7986/mt76) the DFS bring-up wedges hostapd on boot - after a reboot hostapd hangs in D state, phy1 shows NOHT with no beacon, and 5GHz (BrownLightning) never comes up while 2.4GHz is fine. Confirmed live: recovered with `wifi up radio1`. This recurs on every reboot while on a DFS channel. ## Fix Root-cause fix, not a watchdog: non-DFS ch149/HE40 has no radar CAC, so 5GHz comes up instantly and survives reboots. 149/153 is ~6 neighbor APs by scan, still well off the congested 36-48 block. Trades HE80 width for reboot-safety. ## Verify (post-merge) - `iwinfo phy1-ap0 info` -> Channel 149, HT Mode HE40 - `logread` shows a normal bringup with NO DFS-CAC-START line - 5GHz clients reconnect; hostapd in S state 
Regression fix. PR #100 moved 5GHz to DFS ch100 for clean spectrum, but on
this AP (ASUS TUF-AX6000, MediaTek MT7986/mt76) the DFS bring-up wedges hostapd
on boot: after a reboot the main hostapd hangs in D state, phy1 reports NOHT
with no beacon, and 5GHz (BrownLightning) never comes up while 2.4GHz is fine.
A DFS channel requires a ~60s radar CAC on every bring-up, and that CAC hangs.

Fix the root cause instead of automating recovery: move to non-DFS ch149/HE40
(UNII-3). No CAC, so 5GHz comes up instantly and survives reboots. 149/153 is
~6 neighbor APs by scan, still well off the congested 36-48 block. Trade HE80
width for reboot-safety; ample for the ~8 clients on this radio.

README: replace the DFS-spectrum note with the concrete MT7986 boot-wedge
failure mode and the non-DFS guidance.
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