Jason writes –

If you’ve visited the OLPC Wiki, you’ve probably noticed the box on the right hand side that shows the latest releases (stable and development builds). Although the current stable build listed is 650, there’s a newer one (653) that you might want to upgrade to. But if you want the latest, greatest, bleeding edge XO builds, you need to check out the “joyrides”. However, these can be extremely unstable, so be warned.

Before you upgrade, there are a few things to know:

  • You can have two versions of the operating system installed at any time. By default, you’ll boot into the one you installed most recently. So if you start out with build 650, then install build 653 and reboot, you’ll start up in build 653. If you hold down the O key (on the keypad to the right of the screen) as you boot, you’ll boot the alternate operating system (in this case, 650). (At this point, I believe that 650 becomes the default and 653 the alternate.)
  • At boot time, the XO laptop maps a pristine (see /versions/pristine) copy of the operating system into the running system’s filesystem. Any changes you make to the filesystem are in another location (see /versions/run), but it all looks like one filesystem to you. When you reboot into an alternate operating system, any changes you had previously made to it are revived.
  • When you use the olpc-update command to update to a new version of the operating system, the alternate operating system is wiped out (both the pristine version and any modifications to it)
  • Through all of this, your home directory (/home/olpc) is left unchanged.

If you’re ready to install the upgrades, read on – Link.