The ASUS PRIME B550M-A rear panel includes a BIOS FlashBack button
Rear I/O includes: 1x PS/2 combo port, 1x HDMI 2.1, 1x DisplayPort 1.2, 2x USB 3.2 Gen 2 (Type-A and Type-C), 4x USB 3.2 Gen 1 (Type-A), 2x USB 2.0, 1x Realtek 2.5Gb Ethernet, 3x audio jacks (line in/out, mic), and BIOS FlashBack button.
