How to get adb remount to work?

I'm attempting to remove certain files from the SD image mounted on the emulator.

NDUNN-PC ~
$ adb devices
List of devices attached
emulator-5554   device


NDUNN-PC ~
$ adb shell rm -f /sdcard/maps/*
rm failed for -f, Read-only file system

NDUNN-PC ~
$ adb remount
remount succeeded

NDUNN-PC ~
$ adb shell rm -f /sdcard/maps/*
rm failed for -f, Read-only file system

From all the docs I've read, remount is supposed to toggle between read-write/read-only pe开发者_C百科rmissions. But that doesn't seem to work in this case. Any idea what's wrong? Using Windows XP, emulator is running Android SDK 1.6 (with Google Maps APIs).

Removing the -f command from rm made it work. Weird.