There's also a hidden boot to command-line option on the SL-C3000.
It can be a little tricky to access, but here's the steps:
1 - Flip the battery lock switch to the unlock/open (right) position.
2 - Open the battery cover and remove the battery.
3 - Wait approximately 1 minute (sometimes up to an hour)
4 - Press and hold down both the "D" and the "B" keys.
5 - Carefully re-insert the battery while continuing to hold down the D/B keys.
6 - Replace the battery cover and set the switch to lock (left) position (still holding keys).
7 - Continue to hold down the D/B keys and press the power switch.
You should see the standard Sharp splash screen, followed by the linux boot messages.
The following mount points from
ChrisZ may also prove helpful:
/etc is linked from /home: /home/etc -> /etc
/home is mounted from /dev/mtdblock3 type jffs2 (rw, noatime)
/ is mounted from /dev/mtdblock2 type jffs2 (ro, noatime)
...Hope this helps!