I'm using a Raspberry Pi 3B+ with the FreeBSD-12.0-RC1-arm64-aarch64-RPI3.img image. when i try to boot it just goes into the U-Boot command prompt but will not take any of the commands listed when you press tab.
I have tested this image (FreeBSD-12.0-RC1-arm64-aarch64-RPI3.img on a Rasberry Pi 3B (not a +(plus)) and it works correctly, including installing pkg versions of xorg.
It appears that this problem may be RPI 3B+ specific.
Are you using a serial console, or relying on the hdmi/graphics console and a USB keyboard.? If you can and have not please try a serial console connection and see if there are any additional information there.
(In reply to Rodney W. Grimes from comment #1)
I did try the serial console and get the same result, just the u-boot command prompt
It appears there is a different firmware available for the 3B+, i'm not sure if that matters but thought it might since the 3B firmware is in the boot partition
(In reply to Chris Twohig from comment #2)
I have had an independent confirmation that our boot image works with either serial console or a graphcis console and keyboard on A RPI3B+.
How are you making the SD card image your trying to boot?
I extracted the image using 7-zip on windows and wrote it to the SD card with win32diskimager. after i see a fat boot partition and a second which i'm guessing is the / partition
I tested image <FreeBSD-12.0-RELEASE-arm64-aarch64-RPI3.img.xz> on Raspberry Pi 3B+ with success just now.