What is the problem?
Octopi has been running fine for months on my Pi 3 B+. I recently ran apt update && apt full-upgrade -y as I normally do weekly. After a reboot, Wifi connects to my router, and I can ping the Pi from my PC, however, I can no longer access the octoprint web interface or ssh into the Pi. If I plug the ethernet cable in, I can now bi-directionally pass traffic, SSH and access the Octoprint web interface. Ifconfig shows both the eth0 address and the wlan0 address, and no dropped or errored packets show. If I unplug the ethernet cable, communications stop and my ssh connection via the wlan0 ip address times out and disconnects. I can still ping the pi. With a keyboard/Mouse and monitor attached, I can access the internet and my other devices on my network from the pi via wifi.
What did you already try to solve it?
I installed a previous version of the broadcom firmware to see if that was the issue, and no luck.
Additional information about your setup (OctoPrint version, OctoPi version, printer, firmware, octoprint.log, serial.log or output on terminal tab, ...)
Octoprint version 1.3.9, Octopi version 0.15.1
Sep 11 19:48:28 octopi systemd[1]: Started Load/Save RF Kill Switch Status.
Sep 11 19:48:28 octopi kernel: [ 51.743552] brcmfmac: power management disabled
Sep 11 19:48:28 octopi dhcpcd[344]: eth0: waiting for carrier
Sep 11 19:48:28 octopi dhcpcd[344]: wlan0: waiting for carrier
Sep 11 19:48:28 octopi dhcpcd[344]: wlan0: carrier acquired
Sep 11 19:48:28 octopi dhcpcd[344]: all: IPv6 kernel autoconf disabled
Sep 11 19:48:28 octopi dhcpcd[344]: DUID 00:01:00:01:22:69:56:ff:b8:27:eb:bb:2c:82
Sep 11 19:48:28 octopi dhcpcd[344]: wlan0: IAID eb:bb:2c:82
Sep 11 19:48:28 octopi dhcpcd[344]: wlan0: adding address fe80::d9:7171:d6f0:8f22
Sep 11 19:48:28 octopi dhcpcd[344]: if_addaddress6: Operation not supported
Sep 11 19:48:28 octopi dhcpcd[344]: wlan0: carrier lost
Sep 11 19:48:28 octopi picofssd[449]: : Started
Sep 11 19:48:31 octopi dhcpcd[344]: wlan0: carrier acquired
Sep 11 19:48:31 octopi dhcpcd[344]: all: IPv6 kernel autoconf disabled
Sep 11 19:48:31 octopi dhcpcd[344]: wlan0: IAID eb:bb:2c:82
Sep 11 19:48:32 octopi dhcpcd[344]: wlan0: rebinding lease of 10.0.0.195
Sep 11 19:48:32 octopi dhcpcd[344]: wlan0: probing address 10.0.0.195/24
Sep 11 19:48:36 octopi dhcpcd[344]: wlan0: leased 10.0.0.195 for 604800 seconds
Sep 11 19:48:36 octopi avahi-daemon[346]: Joining mDNS multicast group on interface wlan0.IPv4 with address 10.0.0.195.
Sep 11 19:48:36 octopi dhcpcd[344]: wlan0: adding route to 10.0.0.0/24
Sep 11 19:48:36 octopi dhcpcd[344]: wlan0: adding default route via 10.0.0.1
Sep 11 19:48:36 octopi avahi-daemon[346]: New relevant interface wlan0.IPv4 for mDNS.
Sep 11 19:48:36 octopi avahi-daemon[346]: Registering new address record for 10.0.0.195 on wlan0.IPv4.
Sep 11 19:48:36 octopi dhcpcd[344]: forked to background, child pid 520
Sep 11 19:48:36 octopi systemd[1]: Started dhcpcd on all interfaces.
Sep 11 19:48:36 octopi systemd[1]: Reached target Network.
Sep 11 19:48:36 octopi systemd[1]: Starting /etc/rc.local Compatibility...
Sep 11 19:48:36 octopi systemd[1]: Starting Permit User Sessions...
Sep 11 19:48:36 octopi systemd[1]: Starting HAProxy Load Balancer...
Sep 11 19:48:36 octopi systemd[1]: Starting OpenBSD Secure Shell server...
Sep 11 19:48:36 octopi systemd[1]: Started Permit User Sessions.
Sep 11 19:48:36 octopi systemd[1]: Started HAProxy Load Balancer.
Sep 11 19:48:36 octopi systemd[1]: Started OpenBSD Secure Shell server.
Sep 11 19:48:36 octopi systemd[1]: Started /etc/rc.local Compatibility.
Sep 11 19:48:36 octopi systemd[1]: Starting Hold until boot process finishes up...
Sep 11 19:48:36 octopi systemd[1]: Starting Terminate Plymouth Boot Screen...
Sep 11 19:48:36 octopi systemd[1]: Received SIGRTMIN+21 from PID 183 (plymouthd).
Sep 11 19:48:36 octopi systemd[1]: Started Hold until boot process finishes up.
Sep 11 19:48:36 octopi systemd[1]: Started Terminate Plymouth Boot Screen.
Sep 11 19:48:36 octopi systemd[1]: Started Getty on tty1.
Sep 11 19:48:36 octopi systemd[1]: Started Serial Getty on ttyAMA0.
Sep 11 19:48:36 octopi systemd[1]: Reached target Login Prompts.
Sep 11 19:48:36 octopi systemd[1]: Reached target Multi-User System.
Sep 11 19:48:36 octopi systemd[1]: Starting Update UTMP about System Runlevel Changes...
Sep 11 19:48:36 octopi systemd[1]: Started Update UTMP about System Runlevel Changes.
Sep 11 19:48:36 octopi systemd[1]: Startup finished in 5.785s (kernel) + 54.479s (userspace) = 1min 265ms.
Sep 11 19:48:41 octopi systemd[1]: Time has been changed
Sep 11 19:48:41 octopi systemd[1]: apt-daily-upgrade.timer: Adding 36min 52.029217s random time.
Sep 11 19:48:41 octopi systemd[1]: apt-daily.timer: Adding 8h 7min 21.731265s random time.
Sep 11 19:48:57 octopi systemd[1]: Time has been changed
Sep 11 19:48:57 octopi systemd-timesyncd[287]: Synchronized to time server 18.219.136.28:123 (2.debian.pool.ntp.org).
Sep 11 19:48:57 octopi systemd[1]: apt-daily-upgrade.timer: Adding 39min 34.592273s random time.
Sep 11 19:48:57 octopi systemd[1]: apt-daily.timer: Adding 1h 58min 2.462454s random time.
Sep 11 19:51:40 octopi dhcpcd[520]: eth0: carrier acquired
Sep 11 19:51:40 octopi dhcpcd[520]: all: IPv6 kernel autoconf disabled
Sep 11 19:51:40 octopi dhcpcd[520]: eth0: IAID eb:ee:79:d7
Sep 11 19:51:40 octopi dhcpcd[520]: eth0: adding address fe80::20f3:4c46:1284:aadf
Sep 11 19:51:40 octopi dhcpcd[520]: if_addaddress6: Operation not supported
Sep 11 19:51:41 octopi dhcpcd[520]: eth0: rebinding lease of 10.0.0.78
Sep 11 19:51:41 octopi dhcpcd[520]: eth0: probing address 10.0.0.78/24
Sep 11 19:51:46 octopi dhcpcd[520]: eth0: leased 10.0.0.78 for 604800 seconds
Sep 11 19:51:46 octopi dhcpcd[520]: eth0: adding route to 10.0.0.0/24
Sep 11 19:51:46 octopi dhcpcd[520]: eth0: adding default route via 10.0.0.1
Sep 11 19:51:46 octopi avahi-daemon[346]: Joining mDNS multicast group on interface eth0.IPv4 with address 10.0.0.78.
Sep 11 19:51:46 octopi avahi-daemon[346]: New relevant interface eth0.IPv4 for mDNS.
Sep 11 19:51:46 octopi avahi-daemon[346]: Registering new address record for 10.0.0.78 on eth0.IPv4.
Sep 11 19:52:08 octopi systemd[1]: Created slice User Slice of root.
Sep 11 19:52:08 octopi systemd[1]: fake-hwclock.service: Cannot add dependency job, ignoring: Unit fake-hwclock.service is masked.
Sep 11 19:52:08 octopi systemd[1]: Starting User Manager for UID 0...
Sep 11 19:52:08 octopi systemd[1]: Started Session c1 of user root.
Sep 11 19:52:08 octopi systemd[695]: Listening on GnuPG cryptographic agent and passphrase cache.
Sep 11 19:52:08 octopi systemd[695]: Listening on GnuPG cryptographic agent (ssh-agent emulation).
Sep 11 19:52:08 octopi systemd[695]: Listening on GnuPG cryptographic agent (access for web browsers).
Sep 11 19:52:08 octopi systemd[695]: Reached target Timers.
Sep 11 19:52:08 octopi systemd[695]: Listening on GnuPG cryptographic agent and passphrase cache (restricted).
Sep 11 19:52:08 octopi systemd[695]: Reached target Sockets.
Sep 11 19:52:08 octopi systemd[695]: Reached target Paths.
Sep 11 19:52:08 octopi systemd[695]: Reached target Basic System.
Sep 11 19:52:08 octopi systemd[695]: Reached target Default.
Sep 11 19:52:08 octopi systemd[695]: Startup finished in 45ms.
Sep 11 19:52:08 octopi systemd[1]: Started User Manager for UID 0.
Sep 11 21:49:55 octopi kernel: [ 51.231000] EXT4-fs (sda2): re-mounted. Opts: (null)
Sep 11 21:49:55 octopi kernel: [ 51.740222] rtc-ds1307 1-0068: registered as rtc0
Sep 11 21:49:55 octopi kernel: [ 51.890888] brcmfmac: F1 signature read @0x18000000=0x15264345
Sep 11 21:49:55 octopi kernel: [ 51.898702] brcmfmac: brcmf_fw_map_chip_to_name: using brcm/brcmfmac43455-sdio.bin for chip 0x004345(17221) rev 0x000006
Sep 11 21:49:55 octopi kernel: [ 51.900213] usbcore: registered new interface driver brcmfmac
Sep 11 21:49:55 octopi kernel: [ 51.914563] brcmfmac mmc1:0001:1: Direct firmware load for brcm/brcmfmac43455-sdio.txt failed with error -2
Sep 11 21:49:55 octopi kernel: [ 51.998212] sd 0:0:0:0: Attached scsi generic sg0 type 0
Sep 11 21:49:55 octopi kernel: [ 52.971900] brcmfmac: brcmf_sdio_htclk: HT Avail timeout (1000000): clkctl 0x50