Step 1 is upgrade the original Ubiqunti firmware and bootloader. I guess firmware from ver 1.x to 2.x and bootloader from ver 1 to 3.
It has nothing to do with OpenWRT.
On ER4 this was actually two separate updates. But the Ubi support page has good instructions how to do this.
I used pscp.exe and scp the .bin file into the router :\tmp, then I logged in PuTTy and did following: cd /tmp ; sysupgrade -n -v (file .bin) .
After that it says: closing all shell sessions. Commencing upgrade .
Now has been around 10 minutes and I can't still access the GUI through any browser.
So I tried to scp the .bin into the tmp (again) of my router and it says that the host key has been changed.
" C:\Users\angel>scp C:\Windows\System32\openwrt-19.07.4-ramips-mt7621-ubnt-erx-squashfs-sysupgrade.bin root@192.168.1.1:\tmp
@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@
@ WARNING: REMOTE HOST IDENTIFICATION HAS CHANGED! @
@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@
IT IS POSSIBLE THAT SOMEONE IS DOING SOMETHING NASTY!
Someone could be eavesdropping on you right now (man-in-the-middle attack)!
It is also possible that a host key has just been changed.
The fingerprint for the RSA key sent by the remote host is
SHA256:/6v8nzecfPbN2KbW/KxUGOs/OXxARDJKyle3wisDwuA.
Please contact your system administrator.
Add correct host key in C:\\Users\\angel/.ssh/known_hosts to get rid of this message.
Offending RSA key in C:\\Users\\angel/.ssh/known_hosts:1
RSA host key for 192.168.1.1 has changed and you have requested strict checking.
Host key verification failed.
lost connection "
Nothing to do with the router. It is a problem (or security-feature) on your pc. Delete the first line in
C:\Users\angel/.ssh/known_hosts
or the whole file.
Not sure what you mean, but if it is your known_hosts file, then every sysupgrade creates a new ssh or rsa key on the router, which triggers this security feature on your workstation.