It sounds like your Mac mini (M1) is failing to initialize video output after the Sequoia update, which means the usual startup key combinations won’t be effective since Apple silicon Macs don’t rely on Intel-era NVRAM/PRAM or SMC resets. Here’s what I recommend trying step by step:
1. Verify power and peripherals
- Disconnect all external devices except for the display, keyboard, and power cable.
- If possible, try a different display technology (HDMI vs. USB-C). Sometimes the firmware update shifts the default output.
2. Force shutdown and restart
- Press and hold the power button for ~10 seconds until the Mac powers off completely
- Wait a few seconds, then press and hold the power button again. Keep holding it past the Apple logo attempt—on Apple silicon this should bring up Startup Options (gear icon). If you never see this, it means the firmware isn’t loading video properly.
3. Attempt Safe Mode
- If you do get Startup Options, select your startup disk while holding Shift → this forces a Safe Boot and may allow the system to rebuild caches and drivers.
4. Reinstall macOS via Recovery
- From Startup Options, choose Options > Continue to enter macOS Recovery.
- Run Disk Utility > First Aid on your system volume.
- If no issues are found but the system still won’t boot, reinstall macOS Sequoia over your existing installation. This won’t erase your data.
5. If you never get video output
- Connect your Mac mini to another monitor using a different cable type (HDMI if you were using USB-C, or vice versa). Some firmware updates default output to HDMI.
- If absolutely no video appears, even for Startup Options, it suggests a firmware-level issue. In that case, the next step is reviving or restoring the firmware using Apple Configurator 2 from another Mac:
- You’ll need a second Mac, Apple Configurator 2, and a USB-C cable.
- Revive will attempt to reinstall the firmware without erasing data; Restore will erase and fully reload macOS.
6. If you don’t have access to a second Mac
At this point, the only resolution is to bring the Mac mini to an Apple Store or Authorized Service Provider, since they have the tools to revive the firmware.