This is the hardest part. Downloading random .bin files from Google Drive or Bitbucket is a security risk (malware) or a technical risk (wrong version).
Don’t trust random Google Drive links. Here is the professional workflow: dell 5480 bios bin
A corrupted or missing BIOS bin will result in a machine that appears completely dead (no LED, no fan spin) or one that powers on but shows a black screen. This is the hardest part