Broken WiFi Install on Ubuntu (MATE) 21.10 for BCM4306 (rev 03)

[Aaron Pickett]

Device ID:
Network controller [0280]: Broadcom Inc. and subsidiaries BCM4306 802.11b/g Wireless LAN Controller [14e4:4320] (rev 03)

WiFi worked correctly in Ubuntu MATE 20.04. Now I'm getting very slow throughput and constant error messages like the following:

b43-pci-bridge 0000:03:02.0: swiotlb buffer is full (sz: 2390 bytes), total 0 (slots), used 0 (slots)

It sounds like this may be related to errors introduced in b43-fwcutter 1:019-5 with installing the wrong firmware, as reported in Debian bugs #958566 and #960279.

ProblemType: Bug
DistroRelease: Ubuntu 20.10
Package: firmware-b43-installer 1:019-6
ProcVersionSignature: Ubuntu 5.8.0-22.23-generic 5.8.14
Uname: Linux 5.8.0-22-generic x86_64
ApportVersion: 2.20.11-0ubuntu49
Architecture: amd64
CasperMD5CheckResult: skip
CurrentDesktop: MATE
Date: Wed Oct 14 14:52:18 2020
InstallationDate: Installed on 2019-12-08 (311 days ago)
InstallationMedia: Ubuntu-MATE 19.10 "Eoan Ermine" - Release amd64 (20191017)
PackageArchitecture: all
RebootRequiredPkgs:
 bcmwl-kernel-source
 bcmwl-kernel-source
SourcePackage: b43-fwcutter
UpgradeStatus: Upgraded to groovy on 2020-10-12 (2 days ago)

[Aaron Pickett (aaron-d-pickett)]

I attempted to install "bcmwl-kernel-source" as an alternative. As documentation indicated, this did not work with my hardware.

[Aaron Pickett (aaron-d-pickett)]

I manually installed firmware version 5.100.138 using the b43-fwcutter tool, and my throughput has returned to normal. I recommend that the b43 installer package default to this firmware for the BCM4306 (rev 03).

I still get the "swiotlb buffer" spamming my logs, but that might have been happening before.

[Aaron Pickett (aaron-d-pickett)]

Bug has recurred after beta installation of 21.10 (Impish). b43 firmware reverted to version 784.2, causing significant degradation of WiFi performance. using b43-fwcutter to load firmware version 5.100.138 (666.2) resolved the issue.