As a matter of fact, "rm -r folder" could have been working but I always use -rvf and I wasn't seeing any output out of the command so when I did not get back to the prompt in a minute I stopped it. Entering the folder and doing "rm *.jpeg" gave the "too many arguments" error which is usually fixed with a variant of the "find" command with -exec or -delete but it seemed these options are not supported on N9's busybox shell replacement...