I installed Ubuntu v20.04 on my Dell Inspiron 7586 that has come with Intel Dual-Band Wireless 7260 Adapter but when I use the OS as 'Try Ubuntu' everything was working fine except the WiFi which was repeatedly enabling and disabling recursively. I thought installing might resolve the problem but it stayed the same even after installing the OS to the drive partition.
I even tried to figure out if their could be a driver update available at 'Additional Drivers' but except NVIDIA's MX150 driver package nothing was there.
I tried to find the solution over internet for doing it manually as there are no option available like Driver Manager in Windows or Mac that can find the precise driver for the specific hardware component interface. I got the driver from Intel's Support website for Linux
https://www.intel.com/content/www/us/en/support/articles/000005511/network-and-i-o/wireless.html, I downloaded, extracted into /lib/firmware, restarted system but nothing changed.
I thought there might be a driver file inside /lib/firmware that OS recognized as its appropriate driver instead of adapting the right one (i.e in my case the device driver for Dual band 7260 states as iwlwifi-7260-16) so I deleted all the related iwlwifi-* (* indicates all files with prefix iwlwifi-) and only installed the driver file 'iwlwifi-7260-16.ucode' in /lib/firmware but it also didn't help but this time, the WiFi was totally disappeared.
I also tried by downgrading to
19.04, 18.14 and
18.04 version of Ubuntu Distro but the problem remains the same.
The terminal command for
sudo lshw -C network showed this result.
[sudo] password for arslan: *-network UNCLAIMED description: Network controller product: Wireless 7260 vendor: Intel Corporation physical id: 0 bus info: pci@0000:02:00.0 version: 6b width: 64 bits clock: 33MHz capabilities: pm msi pciexpress cap_list configuration: latency=0 resources: memory:91100000-91101fff
Here it states as UNCLAIMED, which I tried to figure online for the solution but found nothing. Unfortunately my laptop which I have currently installed Ubuntu and caught with this issue has no Ethernet and using a WiFi dongle to use internet on my device. With Wireless dongle, the internet works fine.