Hi,
maybe a command line tool which is nearer to the drive can give insight.
Get a list of recognizable optical drives:
xorriso -devices
Insert medium and inspect drive /dev/sr0 for its relation to this medium:
xorriso -outdev /dev/sr0 -list_profiles
If it recognizes the CD-RW and claims to be able to blank and write,
then you should see among others the line
Profile : 0x000A (CD-RW) (current)
The text "(current)" indicates that the medium was recognized as CD-RW.
The text "(CD-RW)" announces that the drive can blank and write the
medium. There will also be a line with "(CD-ROM)", which announces that
the medium type can be read (if it was written and not blanked since).
If you get the complaint:
libburn : SORRY : Cannot open busy device '/dev/sr0' : Device or resource busy
then add an expert command to the xorriso run, before the -outdev command:
xorriso -drive_access shared:unrestricted -outdev /dev/sr0 -list_profiles
If the drive states that it can handle profile "CD-RW", then it would be
time to let it blank the medium.
xorriso -outdev /dev/sr0 -blank as_needed -eject all
or in case of obstinatly being busy:
xorriso -drive_access shared:unrestricted -outdev /dev/sr0 -blank as_needed -eject all
Thie latter might confuse the process which holds the drive occupied or
the Linux kernel which will not know about the new blank state of the
medium. The xorriso run at its end tries to eject the medium in order to
bring any user of the drive to the same perception of the medium state.
(If the drive has no tray motor, please eject manually.)
Burning a new ISO could then be done by:
xorriso -as cdrecord -v dev=/dev/sr0 -eject your_image_file.iso
But your usual burn program is supposed to be able to use that CD-RW
on its own.
Have a nice day
Thomas