Hmm. I might have a factory image for 5.10.1.3. Just finished extraction so haven't installed the factory firmware nor tested if jailbreak still works. Let's pray this works.
EDIT: Eureka! It works!
Won't have time to upload the firmware until much later tonight (US Pacific). Those with PW4 running
5.10.1.3 or older (tested on factory but OTA update is probably ok, too), PM me for the link if you're willing to use your PW4 as guinea pig.