Oh I am sorry to hear that.

AFAIK Magisk couldn't patch all boot.img (including Nova's). I tried this method and got no luck putting Magisk onto my device. Please check the issue list.

https://github.com/topjohnwu/Magisk/issues/755

If you flashed boot.img to 0x00000000 (loader's address), then it is very likely you need to send the device back for service coz the loader mode wouldn't work at all.

Sorry due to Medium's policy I couldn't post the step-by-step rooting guide. Based on my testing the Magisk method is the dead end (but there are ways).

Before sending back for service, maybe it is best to ask one more thing. Could you see "Found One Loader Device"? If you can still see it there would be a slight chance that you can overwrite the loader partition.