There are 4 newer BIOS updates that came after the one you are trying to install. This page has the newest and installation instructions for the procedure from BIOS menu. Just be sure you actually need the update to correct a problem you may be having. I stress caution as the forum is full of posts from BIOS updates that went wrong.
I am trying to install the "Inspiron_7777_5477_AIO_1_2_12" on my AIO 5477 which has been upgraded to Windows 11. The install keeps failing via the Dell Update app and if I download the files and try to install through Windows using the  "Run as Administrator" option or just double clicking on the installation files. I cannot see any options to install via the Bios directly (as someone has previously done for a similar problem). Does anyone have any suggestions to install this update. Thanks    
Bios not installing on Windows 11 AIO 5477