I actually got the same issue with the multicolor flashing lights. Everything went perfect until step 15, but while loading the url, both screens went black, I tried to "continue as if nothing happened", pressed select, waited a few seconds, pushed a random button to reboot, nothing happened, hard resetted the 3ds. It booted and went to the 3ds menu, but it now looks like the one in @
monkeyman4412 's video. I didn't load luma and there is also no otp.bin. Tried it twice after that while having the multicolored screen, same result.