When using the RICOH THETA with the USB API, the camera may be inaccessible.
With the RICOH THETA Z1 and ptpcam, you may see this type of error message.
craig@jetpack-4:~$ theta --info
THETA Device Info
==================
ERROR: Could not open session!
craig@jetpack-4:~$
craig@jetpack-4:~$ theta --capture
Initiating capture...
ERROR: Could not open session!
craig@jetpack-4:~$
After manual unmount
You can use manual unmount.
craig@jetpack-4:~$ theta --info
THETA Device Info
==================
Model: RICOH THETA Z1
manufacturer: Ricoh Company, Ltd.
serial number: '10010104'
device version: 2.10.3
extension ID: 0x00000006
image formats supported: 0x00000005
extension version: 0x006e
Disable Automount
$ sudo apt install dconf-editor
$ dconf-editor
