A little more on coming back from a bootloop without going into recovery.
You can do a factory reset (format data and cache partitions) using fastboot -w.
If the above won't get you out of the bootloop, because of a broken system partition or system apss, you could flash a backup of your system partition, or the system.img file from a rom zip (for example a CM zip).
fastboot flash system system.img
To get to a system partition backup, you can grab a nandroid backup, extract the system.ext4.tar.a file and pack it's content on a .img file (or maybe even rename the file?).
You can also backup your current system partition through the terminal:
dd if=/dev/block/mmcblk0p36 of=/mnt/sdcard/system.img bs=4096
system.img file will be backed up to your internal storage.
You guys think this makes any sense?
Motorola Atrix HD Maxx [4.4.2][CM11 Nightlies]