Some additional, helpful add-ons and comments regarding dual-booting:


Edit as of June 2008: This Post #2 contains some useful tips for using a cloned system and is worth reviewing. However, the usefulness of the HOW TO in Post #1 has been superseded by Penguinbait's great easy-to-use .deb, which automates the whole cloning process. So first check there (and here). Good luck!

I hit the maximum post-length in Post #1, so there are comments about the guide that I put here. You can still just follow the guide as set out in Post #1, but these may be worth looking at. I've also kept this post as a place to put information about additional things you might want to do after you're successfully double-booting.

COMMENTS ON THE GUIDE IN POST #1:

Check bunanson's thread on users' experiences with different brands and types of cards. Also, after you've cloned (or failed at it ), if your experience provides information additional to (or contradictory to) what is on that thread, please take the time to add a post there and enhance the knowledge base.

In Step 8, I originally had:

[backup?] no
[Remove extra stuff?] yes
[Install telnet?] no
[install dropbear?] no

That's what I've used, with success. But I trust fanoush put these options in so that any of them would work, and qwerty12 says that there are important uses for the options I'd declined. Obviously, they remain options. But I've changed Step 8 to comply with qwerty's judgment.

ADD-ONS:

I recommend this extra tweak: Once you are dual-booting, if you have trouble "seeing" your internal card when connected to a computer by USB, see Question #1 and Answer #1 in this post. After making that change, your PC should recognize the SD cards when the Tablet is connected by USB.

I recommend this extra tweak: To get boot menu that defaults to internal card, and to set whether to ask each time or not, enter this code as root:For more info on this and other boot menu tweaks, see the ReadMe in initfs_flasher folder and this post.

If you use Windows and want to make a backup of your partitions (a real backup, not like the included Nokia backup), I suggest Acronis True Image. (Thanks, dont, for the suggestion.) Version 11 works for this; Version 9 does not; I don't know about Version 10. You can even use it to make a copy of your SD card that has the cloned system.

It may be possible to make a back-up (a copy) of your MMC (SD card) entirely within an N800 without any other software. I haven't tried it yet, but see iliaden's post.

Here's a great shortcut from nilchak so you don't have to keep typing "sudo gainroot".

Because of how the MMC works, it is subject to corruption problems. To quote Schmots, "your system can get a little off... if you notice items missing from menus or it's just not working right, reboot to the internal flash and run this command as root from the xterm
The fsck command is a file system checker, the -fy is a force run saying yes to all fixes." I learned this on Schmots's guide to dual-booting, which you might want to check out as an alternative to mine.

A nice addition -- especially for changing between a Flash and MMC boot -- is to be able to soft reboot. See fanoush's instructions. (EDIT: I have to say, I was successful with this once, but unsuccessful on another try. I can't recommend it to someone who isn't pretty comfortable with Xterm, at a minimum. At least, read fanoush's post all the way through before entering any code.)

A trivial (and, oh well, unrelated) enhancement of mine that I like is to eliminate the startup sound. Instructions here.