You want to install your ssh key on a remote server so that you can log into it without a password. Most guides will show you something like this:

user@host:~$ scp ~/.ssh/key.pub remoteuser@remotehost:~/
$ ssh remoteuser@remotehost
remoteuser@remotehost's password:
remoteuser@remotehost:~$ cat key.pub >> ~/.ssh/authorized_keys
remoteuser@remotehost:~$ rm key.pub
remoteuser@remotehost:~$ exit

That's fine, but why not do it in one step?
user@host:~$ ssh-copy-id -i ~/.ssh/key.pub remoteuser@remotehost
remoteuser@remotehost's password:

And you're done.

get developer key for your machine
put it on a usb key in /security folder
plug key in olpc before boot
during splash screen hit escape
at ok prompt type "disable-security" hit enter
olpc no longer needs developer key to run unsigned os images

semi-permanent in that it will not survive if you upgrade the firmware, but it will survive a re-installation of the OS

Your OS image (e.g. os767.img) that you want to upgrade to is corrupted from either being downloaded improperly or copied to your usb drive improperly. For me it was the latter.

Use the md5sum command to compare the file you have copied to your usb drive to the one on the olpc website (md5 sum file is also on the olpc website so you can compare).

If, like me, your file was getting corrupted moving from your desktop where you downloaded the file to your usb drive, try both of the following in sequence.

1) mount the usb drive with the sync option (under gnome 2.24 or newer you can get to this in the drive properties dialog under mount options -- type sync there and remount the device). Note that this option produces more wear on flash drives, and should be turned off after you successfully flash your olpc. On the other hand, if you are regularly getting large files with bits corrupted, especially on a cheap flash drive that you are not worried about, might not be that bad to leave it on.

2) use the cp command from the commandline rather than dragging the file to the usb drive from gnome, it doesn't cheat to make the copying seem faster.

WARNING, THIS WILL DESTROY YOUR DATA IF YOU DO THIS TO THE WRONG DRIVE

shred -vfz -n 0 /dev/xxx

-v is for verbose (this takes a huge amount of time and you really will want progress updates)
-z is for write zeros
-n 0 is for how many passes of totally random data to write first, here none. Feel free to do random passes if you are doing this for data destruction purposes. It takes a long time.

(you should replace xxx with the raw drive, not the partition, e.g. sdd not sdd1. YOU WILL DESTROY YOUR DATA IF YOU DO THIS TO THE WRONG DRIVE. If you need to find out what your desired target disk has been recognized as (may change every boot) run fdisk -l or gparted and look for a disk of the right size and type in the results. BE VERY SURE, and make sure your data is for the current boot (may change).

Were going to New Hampshire, North Carolina, Indiana, Florida, Michigan, New Mexico, Colorado, Nevada......

Thanks Howie!

n/t

Hopefully the country passes the test today.