Having a spare Raspberry Pi 3 and inspired by Vladimír Záhradník's article:
I decided to install OpenWrt on the Pi.
I dd'ed the image openwrt-19.07.5-brcm2708-bcm2710-rpi-3-ext4-factory.img to a 32Gig card, and checked the card with fdisk, expecting to find a fat32 boot partition and a ext4 root partition (similar to Raspbian and implied in the above web page). There was only one big fat32 partition. I tried booting the card in the Pi,but there was no activity.
I'd be grateful for some help to get me started, please!
There should be two partitions, one fat32 which is /boot and one ext4 which is /
Verify with sha256sum that the integrity of the file you downloaded is intact.
If you use dd make sure you output on the whole disk, not just a partition.
Post here the output of the console in case it still doesn't work.
Hmm - I'm not sure that the Pi is booting!
Powering up, the green LED lights up steady, instead of the 'twinkling' that I've usually seen on Pis as they boot. Also, plugging in a monitor with a HDMI cable I get no output.
How long does a Pi 3B take to boot OpenWrt, and should I expect an HDMI output?
The problem proved to be the memory card. I tried a different card (Sandisk) and it booted OK.
I wasn't able to telnet or ssh into the system, but could access it through the web interface.
I'm not sure what strategy I should adopt to swap over from my existing router, with the minimum of problems. I've got a lot of IOT devices on the LAN and am not looking forwards to swapping them all over!
I guess that as OpenWrt's IP addressing conflicts with my current router, I can disable DHCP and change the IP to something vacant on my router. I can then connect it to the LAN where it will be treated as a client and then configure it, until finally swapping over.
RPi3 has one port, which is LAN. Connect your PC directly on the ethernet port, assign an IP from the main router subnet not used by any other device and disable the DHCP server. Then you can connect it to the main network and continue the configurations. Don't forget to assign gateway and dns.