No Wi-Fi Adapter Found | HP 15-ac054tu | BCM43142 [14e4:4365] (rev 01)

Question

I have install Ubuntu 18.04 on this laptop and it shows "No wi-fi adapter found".

It is a UEFI system, but my secure boot is disabled.

Output for sudo lshw -C network:

*-network DISABLED        
       description: Wireless interface
       product: BCM43142 802.11b/g/n
       vendor: Broadcom Limited
       physical id: 0
       bus info: pci@0000:02:00.0
       logical name: wlp2s0
       version: 01
       serial: d8:5d:e2:ce:2f:bd
       width: 64 bits
       clock: 33MHz
       capabilities: pm msi pciexpress bus_master cap_list ethernet physical wireless
       configuration: broadcast=yes driver=wl0 driverversion=6.30.223.271 (r587334) latency=0 multicast=yes wireless=IEEE 802.11
       resources: irq:18 memory:91200000-91207fff
  *-network
       description: Ethernet interface
       product: RTL810xE PCI Express Fast Ethernet controller
       vendor: Realtek Semiconductor Co., Ltd.
       physical id: 0
       bus info: pci@0000:03:00.0
       logical name: enp3s0
       version: 07
       serial: 30:8d:99:23:ee:0b
       size: 10Mbit/s
       capacity: 100Mbit/s
       width: 64 bits
       clock: 33MHz
       capabilities: pm msi pciexpress msix vpd bus_master cap_list ethernet physical tp mii 10bt 10bt-fd 100bt 100bt-fd autonegotiation
       configuration: autonegotiation=on broadcast=yes driver=r8169 driverversion=2.3LK-NAPI duplex=half firmware=rtl8106e-1_0.0.1 06/29/12 latency=0 link=no multicast=yes port=MII speed=10Mbit/s
       resources: irq:117 ioport:1000(size=256) memory:91100000-91100fff memory:91000000-91003fff

Output for lspci -nnk | grep 0280 -A3:

02:00.0 Network controller [0280]: Broadcom Limited BCM43142 802.11b/g/n [14e4:4365] (rev 01)
Subsystem: Hewlett-Packard Company BCM43142 802.11b/g/n [103c:804a]
Kernel driver in use: wl
Kernel modules: wl

I have followed the instructions on this answer, according to which I have installed bcmwl-kernel-source, but nothing seemed to have worked.

I had also installed firmware-b43-installer earlier, as per some other solutions, but that didn't work either.

Edit:

Output of rfkill list:

0: phy0: Wireless LAN
Soft blocked: no
Hard blocked: no
1: brcmwl-0: Wireless LAN
Soft blocked: no
Hard blocked: yes

Edit2:

The output of rfkill list shows that the wifi is hard blocked, which essentially means the wifi is disabled by either some bios setting, a hardware switch/button, or some key on the keyboard.

I have reset the bios and also tried different other combinations - nothing worked. There is no such hardware switch/button on the laptop. Also, there is no wifi disable option through the keyboard. And the point to note is, wifi is working on Windows. Can the hardware block be only for one operating system?

The model number of the laptop is 15-ac054tu from HP.

Edit3:

I even started Ubuntu with live CD, both with Ubuntu 18.04 and 16.04, and installed the driver. It still shows the same thing - hard block.

I searched over the internet with this problem - few more people with the same laptop have exactly the same problem. But couldn't find the right solution for it.

Any help in this regard will be highly appreciable.