my question is theoretical, because I plan to install OpenWrt on a TP Link TL-WR740N v.4.26.
Because there are only 4MB Flash/32MB RAM, it's likely, there will be no GUI available.
I have a bit experience using linux shell, ftp, ssh, telnet, but a "step by step guide" for adjusting configuration would be nice.
Or maybe, are there special builds for low memory devices, with GUI?
The guide can be found here
If there is something not clear there and not on the forum, you could ask here.
Though, it might not be the best idea to start with such router unless you can't ' afford another. You could easily get yourself a suitable used router with 16 MB of flash for $20 or so. That way you will have some space to install few packages, and also you will have better firmware support for the next year or two.
With at least 16 MB of flash and 128 MB of RAM you’ve probably got several years of use. Devices with suitable resources start at under US$20, new. Even 64 MB of RAM is already too tight for many dual-band devices.
Thanks to all for the answers, now I tried a ASUS WL500g Premium v1.
Installation of OpenWRT 18.06 seemed successful, but now no connection to WAN can be established.
I didn't change standard settings, so I should get an IP with DHCP?
My "old" TL-WR740N still works this way.
Wifi is usually disabled by default in OpenWrt, you can enable it in Luci > Network > Wireless, or ssh in, navigate to
/etc/config/wireless and set
option disabled '0'.
edit - although it looks like that's a Broadcom device, so it may not be well supported.
Wifi is not my problem (maybe later), as long as there is no internet connection.
In case of IPoE you probably need to change WAN-interface MAC-address.