WM4.3.5 Issues Upgrading PMP100 AP's from 13.1.3 to 13.4

Subject says it all... I can't seem to get WM4 to upgrade any of our 13.1.3-AP-DES PMP100's to 13.4 FSK/DES. I've double checked that we're using the  CANOPY134BUILDOFFICIAL_DES.pkg3. WM4 goes through the motions... checking status... transferring files... programming... and then finally an error message: "Invalid File Image (status:211)." (if I have auto-update SM enabled) or the error "Invalid File Image (status:218)." if I'm JUST trying to update the AP.

STRANGELY enough... the sm-auto update process updated all of the PMP100 SM's attached to the AP's in question, so those are all updated to 13.4... JUST NOT THE AP!!!

I've tried deleting and re-adding the firmware from the package manager. I've tried re-downloading the firmware on the website. I've tried rebooting the AP before applying the firmware.

I've had no problems using the 13.4 PMP450 firmware in WM4.3.5.