Tinkering with small devices

• Dell Wyse 3040 (F1 retry boot, F2 setup utility (BIOS), F5 onboard diagnostics, F12 Boot menu)
• HP t640
• Intel NUC NUC7I5BNB (F2 BIOS, F7 BIOS update, F10 Boot menu)
• Intel NUC D54250WYB (F2 BIOS, F7 BIOS update, F10 Boot menu)

BIOS update for Dell laptops without battery

Tested with Dell Precision 5530

• Download respective *.exe file from Dell pages
• Copy the *.exe file to root of a FAT32 formatted thumbdrive
• Restart laptop into F12 boot menu, select BIOS Flash Update
• Select *.exe file
• In options field type /forceit
• Start BIOS update

Source

• reddit: Update BIOS without battery?