It works for me too. If you look at the name of the file you posted above its's the RPi3 version you listed. Not the PRi4 version. There's a separate download for the RPi4. It should be in the same download area after you log into the StellarMate site.
When you log onto your SM account, and go to your orders, then downloads, there will be two files, one is for rpi3 and the other rpi4, you have downloaded the incorrect version...
Thanks to everyone who responded. I found the tight build and it installed fine. Only issues so far are "flaky" wireless connection and autoguiding. Likely both are "self-inflicted" problems so I will try again on the next clear night.
I've been running on the RP4 for a couple of months with pretty good success overall. However, with the most recent software updates (the automatic ones you can download from the updater tool on Stellarmate desktop) I am getting the blank black screen on both of my two stellarmates. Trying to burn a fresh copy now to see if it resolves the issue, but wondering if you have had this issue come up again?
I'm experiencing the same just a blank screen. tried flashing the SD card twice using balena etcher on my Raspberry pi 4 8GB. I'm using the StellarMate OS v1.5.2 image downloaded from my orders page in my account.
The Pi boots so far showing me the colour swatch then some script that flashes up to fast to read then blank screen.