Do you see the ring when you re-boot or open the device? Try to swipe from the left or right edge the screen. I have the same problem.
If I swiped from the right, I got a lock screen button. Swiping from the left enabled the camera. The center always showed the rotating ring. Here's what I did that worked for me:
1) The Sailfish os is hidden in the debian linux.img, under /.stowaways You can boot debian and poke around in there to take a look a things.
2) On my linux machine (which I used to Flash the boot/system images), I mounted up the linux.img file in the firmware directory, and created a tar archive of sailfish os:
mount -t ext4 -o ro linux.img /mnt
cd /mnt/.stowaways
tar cjf /where/you/have/space/sailfishos.tar sailfishos
3) Then I rebooted the gemini into debian, went to /.stowaways, and nuked sailfishos. I then sftp'ed the sailfishos.tar from step 2, and extracted it. This resets sailfishos to it's initial state
4) Then I rebooted the gemini, this time into sailfish os, and this time didn't set a PIN. I went through the other initialization steps, logged into my jolla acount, and got the rotating ring again. However, when I rebooted back into sailfish os, it's working fine now.
I hope this helps.
I don't have a SIM installed yet because I'm waiting for Verizon Wireless to decide whether or not they're going to allow the gemini on their network. Until they do, I can't make calls on the gemini so I've gone back to my original phone.