Wireless network seems to be buged if you want to run both interfaces at the same time, see https://dev.openwrt.org/ticket/17659 . A workaround is:
Note: latest trunk has this problem fixed. (tested r44618 and up)
|Version/Model||Launch Date||S/N||OpenWrt Version Supported||Model Specific Notes|
|v1||2011||-||14.07 Barrier Braker||-|
|v2||May 2015||-||Unsupported||Known as RT-N56U B1; sold as regular RT-N56U, box and device indistinguishable from v1|
|v1||Ralink MIPS 74Kc@533MHz||128MiB||8MiB||5 x 1000||Yes 2 x USB 2.0||Yes||Yes|
|v2||MediaTek MIPS 1004Kc@880MHz||128MiB||16MiB||5 x 1000||Yes 2 x USB 2.0||Yes||Unknown|
There are two ways to install OpenWrt. Over the WebUI and TFTP.
Either (recommended if you want a stable system) download a stable version of Barrier Braker squashfs-factory.bin for the initial flash. Use a "sysupgrade" file for any future updates if already on openwrt.
Or (recommended if you need a system with all the newest features and do not care if the system may break) download latest snapshot of Chaos Calmer squashfs-factory.bin for the initial flash. Use a "sysupgrade" file for any future updates if already on openwrt.
Warning: Do NOT flash snapshot image of Chaos Calmer for initial flashing as nothing is ON in snapshot image. This means unless you have a serial connected you will not be able to access the router. You can, however, easily update from a stable release to a daily snapshot, but make sure "Keep Settings" checkbox is checked.
Alternative trunk builds (by moonman) with Luci included. Compiled with -march=74kc instread of -mips32r -mtune=74kc: https://olegtown.pw/openwrt/ As trunk advances some packages become broken and don't build. Be sure to check "broken_packages" directory to make sure a particular build is not missing packages that you need.
untested but should work
|System-On-Chip:||RT3662 (MIPS 74Kc V4.12)|
|CPU/Speed||MIPS 74Kc @ 500 Mhz|
|Flash size:||8 MB|
|Wireless:||Ralink RT3662 + RT3092|
|Ethernet:||RealTek RTL8367M Gigabit w/ vlan support swconfig|
|USB:||Yes 2 x 2.0|
The ports are numbered starting from the USB socket side, Ports 0,1,2 and 3 are LAN and port 4 is the WAN port.
------------------ | XXXX | GND RX TX 3.3 | | | | | | |----------------|57600,8,n,1
the diagram is when viewing the LED side of the board.