Mac mini (M2) fails to boot with red flickering LED light

+1 kaz-k is spot on.

An amber flashing status light, indicates that the M2 Mac mini is in Firmware Recovery Mode.

see > Mac computer status indicator light behavior - Apple Support

If you do not have a qualifying Mac and can not revive/restore the M2 Mac mini's.

see > How to revive or restore Mac firmware - Apple Support

Then take the M2 Mac mini to your local AASP.

see > Find Locations

Hi,

A red flickering or flashing LED light on a Mac Mini (M2) that will not boot up typically indicates a hardware issue, often related to a power supply problem or a logic board failure.

This is a signal that the Mac may need service, so you should take your Mac mini to your local retail AppleStore, Genius Bar or Apple Authorized Service Provider to investigate wether it's a really hardware related issue or software one.

Genius Bar Reservation and Apple Support Options - Apple

Find Locations

I had a similar sounding problem with an M4 mini many months ago and tbirdvet gave me these instructions . . .

Try this process: With Mac off hold down the power button until see it will start in recovery mode. From there you can use disk utilities to check drive and then restart by selecting the internal drive. I did this operation the other day for the same issue you have and it fixed the booting issue. When you do this you may need a wired keyboard and mouse.

It worked although at one point the process seemed to stall and after a while I was just about to shut it down when it suddenly started working OK. So be patient.

I had the same problem with my Mini, a firmware issue that I caused myself by trying to run beta system from an external SSD. Took it into my Apple store and they had me in and out in 45 minutes.

Be sure to have your user account login name and password and your iCloud name and password. They will need it to complete the installation.

Then all you'll need to do is take your Mini home, connect your Time Machine backup drive to it, boot up and have Migration Assistant restore your user data, apps and settings from your TM backup.

If Ian's method doesn't work and you have to take it into the Genius Bar they will erase the drive in their fix. If you don't have a TM backup or some other you may lose all of your user data.

Glad to hear all is well with you. 👍

That is good news. You're welcome.