I'm actually getting good results using the updated brcmfmac43455 firmware files which Raspbian is using. To use them I first removed '/lib/firmware/brcm/brcmfmac43455-sdio.raspberrypi*' then put the brcmfmac43455-sdio* files in the same directory and rebooted.
ubuntu@ubuntu:~$ cat /etc/lsb-release DISTRIB_ID=Ubuntu DISTRIB_RELEASE=18.04 DISTRIB_CODENAME=bionic DISTRIB_DESCRIPTION="Ubuntu 18.04.4 LTS" ubuntu@ubuntu:~$ ip address show wlan0 3: wlan0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc fq_codel state UP group default qlen 1000 link/ether dc:a6:32:37:37:08 brd ff:ff:ff:ff:ff:ff inet 192.168.1.111/24 brd 192.168.1.255 scope global dynamic wlan0 valid_lft 85747sec preferred_lft 85747sec inet6 fe80::dea6:32ff:fe37:3708/64 scope link valid_lft forever preferred_lft forever ubuntu@ubuntu:~$ md5sum /lib/firmware/brcm/brcmfmac43455-sdio.* 963eb0d4903040974ee88b4f85cb1f4f /lib/firmware/brcm/brcmfmac43455-sdio.bin c5aeca0e33de4ae870986c517963fef7 /lib/firmware/brcm/brcmfmac43455-sdio.clm_blob 7b983812a8aee7bf701460436c686226 /lib/firmware/brcm/brcmfmac43455-sdio.txt ubuntu@ubuntu:~$ dmesg | grep brcmfmac [ 12.265990] brcmfmac: F1 signature read @0x18000000=0x15264345 [ 12.271828] brcmfmac: brcmf_fw_alloc_request: using brcm/brcmfmac43455-sdio for chip BCM4345/6 [ 12.284536] usbcore: registered new interface driver brcmfmac [ 12.355127] brcmfmac mmc1:0001:1: Direct firmware load for brcm/brcmfmac43455-sdio.raspberrypi,4-model-b.txt failed with error -2 [ 12.548549] brcmfmac: brcmf_fw_alloc_request: using brcm/brcmfmac43455-sdio for chip BCM4345/6 [ 12.579186] brcmfmac: brcmf_c_preinit_dcmds: Firmware: BCM4345/6 wl0: Feb 27 2018 03:15:32 version 7.45.154 (r684107 CY) FWID 01-4fbe0b04 [ 13.578117] brcmfmac: power management disabled ubuntu@ubuntu:~$ iw dev phy#0 Unnamed/non-netdev interface wdev 0x2 addr 52:4f:c2:5b:63:7a type P2P-device txpower 31.00 dBm Interface wlan0 ifindex 3 wdev 0x1 addr dc:a6:32:37:37:08 ssid Linksys01146_5GHz type managed channel 44 (5220 MHz), width: 80 MHz, center1: 5210 MHz txpower 31.00 dBm For the record I'm connecting to a Linksys EA7450 wireless access point and I've restricted the 5GHz frequency to 802.11ac only. ** Tags added: bionic eoan focal rls-ff-incoming ** Tags removed: rls-ff-incoming ** Description changed: We were not able to completely pin-point the issue yet, so this is more of a blanket bug for the current issues we are seeing. We don't know where exactly the issue can be located. While preparing and testing 18.04.4, certification reported issues with our uc18 images on the pi4 with wifi ac tests. One of our engineers (Brian) confirmed it locally with a wifi access point restricted only to 802.11ac. After some additional testing, he noticed that he had the same unreliable symptoms for both the classic and core images, as well as the 19.10.1 classic images. The symptoms seem to vary, from inability to - detect 802.11ac APs, unability to connect and/or receive an IP address + detect 802.11ac APs, inability to connect and/or receive an IP address and no traffic getting through. - We will provide all the information that we have. Raspbian, after some - initial testing, seems to work better in this regard (though we saw - various reports of it still being a bit flaky). We have tried pulling in - the wifi firmware bits from Raspbian and using those, but the issues - were still the same. + We will provide all the information that we have. Raspbian works better + in this regard. We have pulled in the wifi firmware bits from Raspbian + and using those, and that seems to resolve all flakiness. -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1862760 Title: Unreliable 802.11ac connection on our raspi images To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/linux-firmware/+bug/1862760/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs