Urgent! Can't boot into High Sierra after security update

So basically I fucked my otherwise perfect hackintosh system up by accidentally installing the security update for 10.13

I already tried making another high sierra clover usb stick but it's not working since I tried downloading the high sierra installer app from the appstore on different macs and even a virtualbox with Mountain Lion iAtkos. They all just give me this stump 19mb file instead of the whole 5gb app. Out of frustration I just booted into the recovery partition in clover and tried using timemachine to reset it to an earlier working version- it doesn't boot either. I wasted a few hours already on this crap and nothing seems to work.

What the fuck should I do now? I only have windows 8 at my hands and no real mac to work with. And I need my mac for uni work :(

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