Assuming your drive still shows up as 3,1,0 in -scanbus, try the following.. I hope it works.
$ cdrecord -v dev=3,1,0 driver=mmc_dvdplusrw -format
$ cdrecord -v dev=3,1,0 driver=mmc_dvdplusrw test.iso
You may also wish to try the: -sao/-dao arguments.. DVD+RW format needs to be formatted.
I hope this helps