I have smilar NVR purchased 8CH 960p from Aliexpress I mean external looks are same except 2 USB ports. I have 2 usb ports provision on board but developer has soldered only one !
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I have successfully upgraded Firmware that has new feature of Wireless Extender / Repeater
for using a wireless camera for second camera as an extender
Earlier it was 2.4.x now I have upgraded it to 2.5.x
Also there is 2.6.x but not accepted by NVR so I could not try.
*** Just Take note that 2.5.x has all the ports locked except 80 and not even Telnet is working with physical CAT5 Cable *** Else i could have cracked root password copied from firmware's /etc/password for logging in.
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Now coming to recovery
As per documents there is a recovery Firmware called as help.rom and one has to copy it in USB pen Drive.
help.rom will boot the NVR and then may be you can update the actual firmware after that from second USB pen drive.
yesssss Second usb pen drive ..... so you need 3 port USB Hub or 2 usb ports which will have both the firmwares as my NVR has only one USB port I use hub
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If you want to upgrade firmware on live / running NVR system then connect to NVR on Port 80 via web browser of your ( i.e. your nvr IP ) and upgrade file from your PC, I found this safe as if firmware is not sutiable first it uploads in NVR and stops actual upgrade. In this case you can refresh the webapage and install the old firmware.
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I guess your board is same like mine.
send me email on tgbssk at hotmail dot com
First Have a look and then take decision.
https://support.zositech.com/hc/en-us/articles/115005059608-Upgrade-file-for-NVR-K9608-W
