I looked up in the binary otav3,and made a slight modification. By tweaking a battery related function (sub_1515c), it may always think the device is not ready for update.
I am very unskilled in reverse engineering. So I can't gurantee this will work
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Here is a already modded otav3 binary for PW3:
http://www.mediafire.com/file/yhjwvd...1pw/otav3/file