Is the Z32 paired S2, or just with "None" security?
I think that standalone GBL should work fine, but I always use the ZIP version instead when I do my Zooz updates-- it yields a GBL file when you unzip. Perhaps it's just the very same GBL file. 
If push comes to shove, you can always use these update steps instead -- I wrote them to accommodate S2-paired device updates since the built-in f/w updater can't handle S2. But these steps work just fine for devices paired with no security too.
I've updated lots of Zooz devices and a few Leviton devices using these steps, and these steps have never failed me.
