It's possible, apparently.
http://forum.xda-developers.com/g4/general/recover-data-bootlooping-phone-t3313869
I haven't tried myself, but the zip file and tool is confirmed as working in that thread.
http://forum.xda-developers.com/g4/general/recover-data-bootlooping-phone-t3313869
I haven't tried myself, but the zip file and tool is confirmed as working in that thread.