I have Netgear EX6420, I try upload openwrt firmware but I can't ( wrong firmware) I try ex6400 firmware but it's wrong and ex7300 firmware again it's wrong.
Now, original firmware: https://kb.netgear.com/000064217/EX6250-EX6400v2-EX6410-EX6420-EX7300v2-EX7320-Firmware-Version-1-0-0-146
it's the same for ex6400, ex6420 and ex7300.
My question is why openwrt has not firmware for ex6420?
Is there way try upload ex6400 firmware in my ex6420?
The OEM firmware performs a basic sanity check based on some specific strings it expects in what you upload. As you can see, these are not there in the OpenWrt images you tried.
Since OpenWrt cannot know (or guess) which kind of magic Netgear uses to provide one unified image for those (seemingly?) similar devices, you cannot expect OpenWrt to provide images for hardware it was never actually ported to. The person who introduced support for the EX6400 had that hardware to work with.
If you are a 100% sure that the hardware is identical, you can try to force flash it (e.g. by verifying which check the OEM firmware is performing and working around that). But that's still completely at your own risk.
thank you for reply, but I never forced upload firmware and I don't know how force upload firmware.
No problems, I understand it's completely my risk, I think I can recovery original firmware I'm using "nmrpflash" https://github.com/jclehner/nmrpflash it works very well with my ex6420.