The NVR is going to reject the firmware if it's wrong typically. I've had this happen on many occasions and it has saved me.
Back with early versions of 3.x.x, (pre-3.3.x) upgrading to later versions of 3.x.x (3.3.x+) would cause the NVR to scramble up the login information. On 7700s, the workaround was to use 3.1.7 as intermediary firmware, then upgrade to the latest version. This prevented the lockup from happening. In my case, this worked 100% of the time provided you factory reset before doing anything.
In the case of the 7600, that was not a viable option as it would still brick. However, I recently upgraded a 7600 from 3.0.3 to 3.4.2 and while it did scramble up the login information, it at least let me go into settings to perform a factory reset. That took care of everything in 2 steps, no TTL required.
Moral to the story, you may not have flashed the wrong firmware, it may have simply just been a fluke much like the ones I described. In any case, if no matter what it won't let you in, then a USB-TTL adapter and some soldering (UART connector can help you avoid soldering, I could never find one) may be required to recover it.
This is the correct firmware:
http://www.hikvisioneurope.com/port...) 7700NI-E4/V3.4.6 build160405 Multi-lingual/
Why does your computer have 3 NICs? While I've successfully had the
TFTP tool work on wifi and Ethernet simultaneously, by no means do I recommend it. Unhook 2 or disable them until your sort this out. Don't make yourself more problems than you already have.
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