Comment 0 for bug 1866697

When I upgraded an older Macbook Air (running Ubuntu 18.04.4) from kernel 4.15 to 5.5, the wifi adapter no longer worked. The system was reporting that there were no wifi adapters found.

I did research, tried some of the suggested changes (mostly installing the DEB package with the Broadcom kernel source) and had no luck getting wifi to work.

Installed kernel 5.3.18 and the wifi adapter is found and is working.

cat /proc/version_signature returns 'no such file'

lscpi -vnvn returns (for the wifi adapter):

03:00.0 Network controller [0280]: Broadcom Inc. and subsidiaries BCM4360 802.11ac Wireless Network Adapter [14e4:43a0] (rev 03)
 Subsystem: Apple Inc. BCM4360 802.11ac Wireless Network Adapter [106b:0117]
 Control: I/O- Mem+ BusMaster+ SpecCycle- MemWINV- VGASnoop- ParErr- Stepping- SERR- FastB2B- DisINTx-
 Status: Cap+ 66MHz- UDF- FastB2B- ParErr- DEVSEL=fast >TAbort+ <TAbort- <MAbort- >SERR- <PERR- INTx-
 Latency: 0, Cache Line Size: 256 bytes
 Interrupt: pin A routed to IRQ 0
 Region 0: Memory at b0600000 (64-bit, non-prefetchable) [size=32K]
 Region 2: Memory at b0400000 (64-bit, non-prefetchable) [size=2M]
 Capabilities: [48] Power Management version 3
  Flags: PMEClk- DSI- D1+ D2+ AuxCurrent=0mA PME(D0+,D1+,D2+,D3hot+,D3cold+)
  Status: D3 NoSoftRst+ PME-Enable- DSel=0 DScale=2 PME-
 Capabilities: [58] MSI: Enable- Count=1/1 Maskable- 64bit+
  Address: 0000000000000000 Data: 0000
 Capabilities: [68] Vendor Specific Information: Len=44 <?>
 Capabilities: [ac] Express (v2) Endpoint, MSI 00
  DevCap: MaxPayload 256 bytes, PhantFunc 0, Latency L0s <4us, L1 unlimited
   ExtTag- AttnBtn- AttnInd- PwrInd- RBE+ FLReset- SlotPowerLimit 10.000W
  DevCtl: Report errors: Correctable- Non-Fatal- Fatal- Unsupported-
   RlxdOrd+ ExtTag- PhantFunc- AuxPwr+ NoSnoop+
   MaxPayload 128 bytes, MaxReadReq 1024 bytes
  DevSta: CorrErr- UncorrErr+ FatalErr- UnsuppReq- AuxPwr+ TransPend-
  LnkCap: Port #0, Speed 2.5GT/s, Width x1, ASPM L0s L1, Exit Latency L0s <2us, L1 <32us
   ClockPM+ Surprise- LLActRep- BwNot- ASPMOptComp+
  LnkCtl: ASPM L0s L1 Enabled; RCB 64 bytes Disabled- CommClk+
   ExtSynch- ClockPM+ AutWidDis- BWInt- AutBWInt-
  LnkSta: Speed 2.5GT/s, Width x1, TrErr- Train- SlotClk+ DLActive- BWMgmt- ABWMgmt-
  DevCap2: Completion Timeout: Range ABCD, TimeoutDis+, LTR+, OBFF Via WAKE#
  DevCtl2: Completion Timeout: 50us to 50ms, TimeoutDis-, LTR+, OBFF Disabled
  LnkCtl2: Target Link Speed: 2.5GT/s, EnterCompliance- SpeedDis-
    Transmit Margin: Normal Operating Range, EnterModifiedCompliance- ComplianceSOS-
    Compliance De-emphasis: -6dB
  LnkSta2: Current De-emphasis Level: -3.5dB, EqualizationComplete-, EqualizationPhase1-
    EqualizationPhase2-, EqualizationPhase3-, LinkEqualizationRequest-
 Capabilities: [100 v1] Advanced Error Reporting
  UESta: DLP- SDES- TLP- FCP- CmpltTO- CmpltAbrt- UnxCmplt- RxOF- MalfTLP- ECRC- UnsupReq- ACSViol-
  UEMsk: DLP- SDES- TLP- FCP- CmpltTO- CmpltAbrt- UnxCmplt- RxOF- MalfTLP- ECRC- UnsupReq- ACSViol-
  UESvrt: DLP+ SDES+ TLP- FCP+ CmpltTO- CmpltAbrt- UnxCmplt- RxOF+ MalfTLP+ ECRC- UnsupReq- ACSViol-
  CESta: RxErr- BadTLP- BadDLLP- Rollover- Timeout- NonFatalErr-
  CEMsk: RxErr- BadTLP- BadDLLP- Rollover- Timeout- NonFatalErr+
  AERCap: First Error Pointer: 00, GenCap+ CGenEn- ChkCap+ ChkEn-
 Capabilities: [13c v1] Device Serial Number 48-d7-00-ff-ff-00-00-01
 Capabilities: [150 v1] Power Budgeting <?>
 Capabilities: [160 v1] Virtual Channel
  Caps: LPEVC=0 RefClk=100ns PATEntryBits=1
  Arb: Fixed- WRR32- WRR64- WRR128-
  Ctrl: ArbSelect=Fixed
  Status: InProgress-
  VC0: Caps: PATOffset=00 MaxTimeSlots=1 RejSnoopTrans-
   Arb: Fixed- WRR32- WRR64- WRR128- TWRR128- WRR256-
   Ctrl: Enable+ ID=0 ArbSelect=Fixed TC/VC=ff
   Status: NegoPending- InProgress-
 Capabilities: [1b0 v1] Latency Tolerance Reporting
  Max snoop latency: 3145728ns
  Max no snoop latency: 3145728ns
 Capabilities: [220 v1] #15
 Kernel modules: bcma

lsb_release returns:

Description: Ubuntu 18.04.4 LTS
Release: 18.04

apt-cache for the driver kernel source returns:

bcmwl-kernel-source:
  Installed: 6.30.223.271+bdcom-0ubuntu5
  Candidate: 6.30.223.271+bdcom-0ubuntu5
  Version table:
 *** 6.30.223.271+bdcom-0ubuntu5 100
        100 /var/lib/dpkg/status
     6.30.223.271+bdcom-0ubuntu5~18.04.1 500
        500 http://us.archive.ubuntu.com/ubuntu bionic-updates/restricted amd64 Packages
     6.30.223.271+bdcom-0ubuntu4 500
        500 http://us.archive.ubuntu.com/ubuntu bionic/restricted amd64 Packages

What I expected to happen: Wifi connection (and icon showing in status bar)
What happened instead: WiFi adapter not found.