The Sony CDU-924 was the first drive that has no hardware support
for CDROM XA2 mode 1. If you want to create a multi session disk,
you need to switch back to -data (plain CD-ROM)

From the current information, it seems that _all_ Sony drives
lack this XA2 support.

For all Sony drives you need to call cdrecord -multi -data
if you like to create multi-session CD's.

Sony drives do not allow to write XA2 tracks with
hardware support of the drive.

There is currently a bug in the Sony code (for _old_ non MMC drives)
of cdrecord that does not allow you to have different track types 
in one session.

All Sony drives that have CDUxxx type names are _old_ non MMC drives.

All Sony drives that have CRXxxx type names are MMC compliant.

NOTE: many HP CD-writers are nased on Sony OEM drives.