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Hotspot won't start while your WiFi is on 5 GHz

You're connected to a 5 GHz network and apsta start refuses:

Your WiFi is connected on 5 GHz channel 44, where this card isn't allowed to
start a network (marked "no IR" by its firmware/regulatory rules). It can only
run the hotspot on the same channel as your WiFi.

On older versions you saw driver errors instead, such as hostapd "not broadcasting" or NetworkManager's "No suitable device found".

The same laptop may have worked fine yesterday. What changed is the network you're connected to, not apsta.

Newer apsta handles this on most Intel cards. If apsta detect shows "Wi-Fi Direct group on its own channel: yes", apsta no longer refuses: the hotspot runs as a Wi-Fi Direct group on a channel of its own, the way Windows' Mobile Hotspot does (see the Wi-Fi Direct fallback). The same goes for networks on radar (DFS) channels 52–144, common on campus and office networks. The rest of this page is about cards that can't do that, and the fixes for them.

Why it happens

Two rules of your WiFi card combine.

1. The hotspot must use the same channel as your WiFi. Most laptop cards (Intel, Realtek, most MediaTek) have one radio. To be connected to WiFi and run a hotspot at the same time, both have to sit on one channel. If your WiFi is on channel 44, the hotspot has to be on 44 too. apsta detect shows this as "The hotspot will use the same channel as your WiFi connection."

2. The card may not be allowed to start a network on that channel. Radio rules differ by country. To stay within them without knowing where it is, the card's firmware lets it join networks on many 5 GHz channels but only start one on a few. Channels where it can only join are marked "no IR" (no "initiating radiation"). On Intel cards that's typically 5 GHz channels 36–144; channels 149–165 and all 2.4 GHz channels are usually allowed.

Put together:

flowchart TD
    A["Laptop connected to WiFi<br/>on channel 44 (5 GHz)"] --> B{"Can the card use two<br/>channels at once?"}
    B -- "yes (rare), or as a Wi-Fi Direct<br/>group (most Intel cards)" --> OK1["Hotspot on its own<br/>allowed channel ✔"]
    B -- "no (most laptops)" --> C["Hotspot must also use channel 44"]
    C --> D{"May the card start a<br/>network on channel 44?"}
    D -- "yes" --> OK2["Hotspot on channel 44 ✔"]
    D -- "no: marked no IR" --> FAIL["No hotspot ✘<br/>apsta explains and suggests fixes"]

The firmware enforces this, and apsta doesn't override it. On Intel cards the firmware is often stricter than the law where you are; see fix 4 if you want to change that yourself.

Common situations:

  • Phone hotspot as your internet. Many phones (Xiaomi/Redmi, Samsung, Pixel) run their hotspot on 5 GHz, and some switch bands on their own. That is why it can work one day and not the next.
  • Dual-band router with one name for both bands. Your laptop picks 5 GHz when the signal is good.

Check whether you're affected

apsta detect

shows a warning and a "Hotspot on 5 GHz" row:

✔  Your card can run a hotspot while staying connected to WiFi.
⚠  Your WiFi is on 5 GHz channel 44, where this card can't host.
⚠  Switch that network to 2.4 GHz, or connect to a 2.4 GHz network, then start.
⚠  Why: https://github.com/krotrn/apsta/blob/main/docs/5ghz-wifi.md

The raw data: iw dev shows your WiFi channel, and iw phy phy0 info lists every channel. The ones marked (no IR), (radar detection) or (disabled) can't host.

No warning doesn't mean you're safe for good: a network that switches bands by itself can be on 2.4 GHz now and on 5 GHz in an hour. See the next section.

When the network switches band while the hotspot is running

Phone hotspots set to an automatic band (often the default) move between 2.4 and 5 GHz by themselves, without you touching anything. Your laptop follows, because it has to stay on the phone's channel. You can see it in the system log:

journalctl -k | grep "switches to different band"

wlo1: AP aa:bb:cc:dd:ee:ff switches to different band (5220 MHz, ...), disconnecting

If it moves to a channel your card can't host on, the hotspot can't keep running there. Worse, while the hotspot holds the old channel your laptop can't follow the phone either, so you'd have no internet at all. apsta watches for this and steps aside:

sequenceDiagram
    participant P as Phone hotspot
    participant L as Laptop WiFi
    participant W as apsta watcher
    Note over P,L: both on 2.4 GHz channel 11, hotspot running
    P->>L: "Moving to 5 GHz channel 44"
    L--xP: disconnects (the hotspot holds channel 11)
    W->>W: notices within ~20 s: WiFi lost or moved
    W->>L: stops the hotspot
    L->>P: reconnects on channel 44, internet is back
    alt card supports a Wi-Fi Direct group on a second channel
        W->>W: starts the hotspot as a group on its own channel
    else
        loop every 10 s, then less often (up to 5 min)
            W--xW: try to start: channel 44 is "no IR"
        end
        P->>L: later: "Moving to 2.4 GHz channel 6"
        W->>W: next try succeeds: hotspot on channel 6
    end

The watcher runs however you start the hotspot: with sudo apsta start or the GUI it runs in the background as apsta-watch.service; with sudo apsta enable (or sudo apsta run in a terminal) the service itself does it. sudo apsta stop stops the watcher too. To see what it's doing:

journalctl -u apsta-watch    # started with apsta start or the GUI
journalctl -u apsta          # started with apsta enable

On cards without the Wi-Fi Direct fallback, while the network stays on such a channel you get internet but no hotspot. The lasting fix is to stop the network from switching: set its band to 2.4 GHz explicitly (below).

On systems without systemd, a hotspot started with apsta start isn't watched: run sudo apsta stop to get your WiFi back, or use sudo apsta enable.

Fixes

Pick whichever suits you:

  1. Move your WiFi to 2.4 GHz. Simplest, keeps everything else the same.
  2. Phone hotspot: Settings → Hotspot → AP band → 2.4 GHz (the wording varies; on Xiaomi/Redmi: Connection & sharing → Portable hotspot → Set up portable hotspot → AP band). Pick 2.4 GHz explicitly: "auto" or "5 GHz preferred" can switch back to 5 GHz at any time.
  3. Router: connect to its 2.4 GHz network. If both bands share a name, many routers let you split them in their settings.

Then reconnect and run sudo apsta start.

  1. Get internet another way, then let apsta drop WiFi. For example, plug the phone in with USB and turn on USB tethering, or use ethernet. Then:
sudo apsta start --allow-disconnect

apsta disconnects the WiFi and hosts on a channel the card allows (for example 5 GHz channel 149, which is fast). Internet comes over the cable.

  1. Use a USB WiFi adapter for the hotspot. It has its own radio, so your built-in card can stay on any channel:
sudo apsta start --interface wlan1

apsta recommend lists adapters with in-kernel Linux drivers.

  1. Intel cards: let the kernel decide (advanced). Intel cards keep their own copy of the radio rules in firmware (LAR, location-aware regulatory) and are often stricter than the law. For example, India allows hosting on 5 GHz channels 36–48, but an Intel AX201 still marks them "no IR":
iw reg get          # "global" = the kernel's rules, "phy#0 (self-managed)" = the firmware's

global
country IN: DFS-UNSET
 (5150 - 5250 @ 80), (N/A, 30), (N/A)        ← channels 36–48: allowed, no radar rules
phy#0 (self-managed)
 * 5220.0 MHz [44] (22.0 dBm) (no IR)         ← the firmware says no

If the kernel's rules for your country allow a channel the firmware blocks, a patched driver can hand the decision back to the kernel. The iwlwifi driver used to have a lar_disable=1 option for this; it was removed. The linux-wifi-hotspot project keeps a patch and scripts that restore it. Follow their guide; in short:

lsmod | grep -E '^iwl(dvm|mvm|mld)'   # must say iwlmvm (AX2xx and older); iwlmld is not supported
cd util/iwlwifi-lar-disable && ./build.sh
sudo COUNTRY=IN ./install.sh          # your own two-letter country code
sudo reboot

Afterwards iw phy phy0 info shows no "(no IR)" on the channels your country allows, and sudo apsta start works on them with no other change.

Before you do this:

  • You become responsible for the radio rules. Set the country you are actually in. The patch doesn't grant spectrum, it only stops the firmware being more careful than the law.
  • It replaces a kernel module. It has to be rebuilt after every kernel update (on rolling distributions such as Arch, that's often), and with Secure Boot on you must enroll a signing key first.
  • Radar channels (52–144) stay off-limits. Hosting there needs radar detection, which client cards don't do.
  • apsta doesn't ship or run this patch; it's a change to your system's driver, so it stays your decision.

The Wi-Fi Direct fallback

Many cards that pin a normal hotspot to the WiFi's channel can run a Wi-Fi Direct group owner on a second one (most Intel cards). When the WiFi's channel can't host, apsta starts one through NetworkManager's wpa_supplicant (method p2p) on a channel the card allows, with your usual name and password. The radio switches between the two channels, so the hotspot and your WiFi share its speed; that's why apsta still prefers the same channel whenever it works.

wifi-direct.md explains which cards and distributions support it, the trade-offs, and how it works.

What apsta doesn't work around

  • Hosting on the "no IR" channel anyway: the firmware refuses. Where the firmware is stricter than the law, the fix is in the driver (fix 4), not something a hotspot tool should do behind your back. The kernel's "IR-concurrent" exception (hosting on a no-IR channel you are already connected on) applies only to Wi-Fi Direct groups, not to a normal hotspot, and distributions don't enable it.
  • Cards without a second channel for Wi-Fi Direct: there is no other way to keep WiFi and host elsewhere.

So on those cards apsta tells you up front and suggests the fixes above, instead of trying and failing with driver errors.