From 3b3f2dbac738e2652628980078c65271fb5d4971 Mon Sep 17 00:00:00 2001 From: Matti Airas Date: Thu, 27 Aug 2026 11:16:52 +0300 Subject: [PATCH] docs(networking): recommend the minimal WiFi firmware for AP use The CYW43455 standard firmware seizes up in practice with only a few access point clients connected, and then admits none at all. Raspberry Pi OS ships a minimal variant selected through update-alternatives, and the docs never mentioned it. Recommend it for any device whose hotspot is in real use, record the switch, what the minimal variant gives up (DFS radar detection, automatic channel selection, roaming assistance, antenna diversity), and how to revert. Co-Authored-By: Claude Opus 5 (1M context) --- docs/user-guide/networking.md | 30 ++++++++++++++++++++++++++++++ 1 file changed, 30 insertions(+) diff --git a/docs/user-guide/networking.md b/docs/user-guide/networking.md index 13c0e7c..7c3245d 100644 --- a/docs/user-guide/networking.md +++ b/docs/user-guide/networking.md @@ -35,6 +35,36 @@ This lets you reach the device without Ethernet. The hotspot has no internet of When the device joins a WiFi network, it keeps the hotspot running and acts as a client at the same time (concurrent AP and client). To do this it moves the hotspot onto the client network's channel, so a device connected to the hotspot may briefly disconnect and reconnect on its own. For the full first-time walkthrough, see [First Boot — WiFi access point](../getting-started/first-boot.md#wifi-access-point-headless-images-and-the-ap-desktop-variant). +### Serving more access point clients + +The WiFi chip (Cypress CYW43455) has two firmware variants, and the system chooses between them with `update-alternatives`. The default `standard` variant accepts about 7 access point clients. The `minimal` variant is tuned for access point use and accepts about 19. + +Use the `minimal` variant on any device whose hotspot is in real use. The client count is the smaller reason: in practice the `standard` variant seizes up with only a few clients connected, and then admits none at all. + +Switch the variant: + +```bash +sudo update-alternatives --config cyfmac43455-sdio.bin +``` + +Select the `cyfmac43455-sdio-minimal.bin` entry, then reboot. `update-alternatives` records the choice, so later firmware package updates keep it. + +The `minimal` variant frees the chip memory for those extra client slots by dropping features: + +- Automatic channel selection. +- DFS radar detection, so the 5 GHz channels that require it become unavailable. +- 802.11k/v/r roaming assistance and antenna diversity. + +It is also an older firmware release than the `standard` variant (7.45.241 from 2021, against 7.45.265 from 2023). + +If the hotspot does not come up after the switch, set a fixed channel on it, because the `minimal` variant cannot pick one on its own: + +```bash +sudo nmcli connection modify Halos-AP wifi.band bg wifi.channel 6 +``` + +To go back to the default firmware, run the same command and select the `standard` entry, or run `sudo update-alternatives --auto cyfmac43455-sdio.bin`. + ## Ethernet Ethernet works out of the box with DHCP. The device obtains an IP address automatically from your network's DHCP server.