Is there any tool available to properly wipe empty storage space on N900, before you sell it or give it to someone else? I suppose that resetting it to default settings is one thing, which should be followed by some DoD compliant safe wipe.

The memory card is no fuss, as you can probably just put it into a card reader and use sdelete or similar on a Windows computer to wipe it. Could the same apply to the onboard storage (i.e. you connect N900 as "mass storage", and use sdelete on that "drive"), or is there a better solution?

http://wiki.maemo.org/Updating_the_firmware

Flash both rootfs and emmc.

rm -Rf /home/user/MyDocs/*

Please don't do that, unless you're willling to spend time with this person fixing what's broken after applying your commands...

If you don't want to help, either tell him to RTFM, to google or to use search but please refrain from giving harmfull commands to people who might not understand the implications if they follow your advise...

Notice the word "properly" in the title?

What's improper there? The FAT32 partition is housed entirely in that directory. No data that resides there will harm the operating system if removed.

It won't remove installed applications or their saved preferences, but that wasn't what the OP was asking to do.

Folks should stop being so damned frightened of the command line.

Step 1: Become superuser, issue command
Step 2: Reflash device

Step 3: Hand over device

It won't delete contacts and conversation history either, which is what you usually want to do when you are selling the phone. On the other hand, it will remove all directories, not just files in them, which means that the new owner won't be able to take pictures, browse or even download maps, and who knows what else.

If you want to just wipe the MyDocs partition then a better way is press and hold in File Manager->Format.

I agree with that. However, the method to make people feel more secure is to give them understanding of their device.

Not sure the rm would have been up to the task, if you get what I mean.

The OP didn't ask how to delete contacts or history. He asked how to delete the storage space. He even detailed how one option included formatting from a desktop PC using the Mass storage USB mount. The rm command I posted does exactly the same thing only easier.

Removing the directories from MyDocs harms NOTHING. All of the directories used by internal applications like maps and pictures would be automatically regenerated the next time those applications were started and instructed to write to the path name.

Where is the FUD coming from? Screwing with the MyDocs contents will delete media, but will not harm the N900's normal operation.

Agreed that rm -Rf is not the most fool proof method of data removal, even dd is not perfect if only run once. But this isn't a CIA laptop here, it's a phone and we shouldn't scare people away from simple to perform commands that provide a commonly acceptable method of data removal just because of blanket FUD like:
"Who KNOWS what could happen!!?!?!"

Head's up: We know what would happen. The data would be removed, and the N900 would still work. Get over it.

I tried downloading some maps via Nokia PC Suite. It claimed Nokia Maps was not installed on my device. The reason was that, not realizing its purpose, I had previously foolishly deleted the .qf file in MyDocs root.