We just received 4x Linksys EA8500 routers at work which were unused for 4 years I thought I'd grab one and OpenWRT it.
If you just bought this router, only connect it to your PC via one of the 4 ETH ports and not your main router via WAN, because these god damn OEM routers autoupdate without even asking you if they see a sign of internet.
- Download the v1.4.4 factory image & OpenWRT.
- Flash the v.1.4.4 image via settings
- Wait for reboot
- Flash the v.1.4.4 image again via settings
(This router has an A/B boot partition scheme, hence why you need to flash the factory firmware twice)
- Flash the previously downloaded OpenWRT bin (once, because if that one fucks up; you can still go back to OEM firmware)
- Voilà !
If any of this fucks up, remember it uses A/B partition scheme.
The main sign of flashing bad fw is the screen with "Linksys" on it not turning on.
If that's the case, reboot into the B partition by turning the router off, turning it on for 2 second, then turning it off and repeating that 2 times:
turn off, turn on, wait 2s, turn off, turn on, wait 2s, turn off, turn on, wait 2s, turn off, turn on
If flasing the 1.4.4 firmware makes the screen not turn on, do the above procedure, update to latest from the linksys site (twice), then downgrade back to 1.4.4 (twice).
Even if the linksys site says "US Only" for 1.4.4, that is not the case.
Holding the reset button while in OpenWRT will reset the OpenWRT config and will not go back to factory linksys firmware.