I’ve had a similar problem with my Z1 a number of times. Were you able to fix the problem?
You can try connecting your Z1 as a storage device to to a Windows computer, then save all your media to a safe location on your laptop or cloud. After your media is saved, delete all media from the Z1. Reboot camera.
if the “easy” fix of deleting media doesn’t work
If you are desperate and the camera is bricked, you can try more aggressive techniques if you have exhausted all other normal things such as calling RICOH support.
There are a couple of fixes that worked for me. I’m not recommending either of the techniques below, but I am just sharing what worked for me.
wipe all data and apps with Vysor Factory Reset
camera must be in developer mode (free)
camera must be able to boot briefly, at least long enough for you to access Vysor
reboot bootloader with adb shell
camera must be in developer mode (free)
I’m not sure what this actually does, but my camera booted