Sound lost again from Dell Inspiron 15

Download BIOS file from Dell. If you have Windows, execute the .exe. If you don’t have Windows, boot with a WindowsPE disk and navigate to the location of the .exe file. Execute the update. Hirens BootCD is a good example of a free, WindowsPE disk.

https://www.hirensbootcd.org/download/

Or try with `fwupdmgr. See the following: