Save my weekend? Can't flash on Windows "Fatal Bad Memory Block"?

So I have an mr1750 and a pair of OM5Pac access points to flash this weekend and I think since I updated to Win 10 this past week something is up with WinPCap according to my initial Google hunt.

This is what happens when I try to flash it (Command Prompt running as Admin):

ap51-flash.exe 8 lede-17.01.4-ar71xx-generic-mr1750-squashfs-factory.bin
FATAL Bad Memory Block.
FATAL Bad Memory Block.
FATAL Bad Memory Block.

I tried installing npcap-0.99.r5 but no luck. Anyone familiar with this tool, is there a debug flag?

Thanks!

I was a bit rushed, but these are all Open Mesh brand access points.

Can you run Linux somehow, or use serial?

I think ap51flash works by Telnetting into the bootloader, which you can also do manually. But it has been a long time.