I accidently ran an 'opkg upgrade' and it destroyed my intel edison. If you still have wifi, or a console, these are the steps needed to restore it:
mkdir /update
mkfs.vfat -F32 -I /dev/mmcblk0p9
mount -t vfat /dev/mmcblk0p9 /update/
cd /update
wget http://downloadmirror.intel.com/25384/eng/edison-iotdk-image-280915.zip
unzip edison-iotdk-image-280915.zip -d .
rm edison-iotdk-image-280915.zip