Airlink101 AR670W
The Airlink101 AR670W is a 802.11n router.
Note: As of r43153 this model is supported in the upstream OpenWrt trunk, and will thus be a part of the upcoming Chaos Calmer release.
This fork is stable and fully functional on the AR670W. The hardware components are well-supported in Attitude Adjustment.
- CPU: Ralink RT2880 SoC (MIPS 4KEc) at 266MHz
- RAM: 32MB
- Flash: 4MB
- Ethernet: 100Mbit on a 5-port IP175C switch
- Wireless: Ralink RT2872
- Expansion: mini-PCI header, unpopulated
- JTAG: yes, unpopulated
- Serial: 57600bps, populated, Linux sees as ttyS1
Pin 1 Rx
Pin 2 ABSENT
Pin 3 3.3V
Pin 4 GND
Pin 5 Tx
For some reason, the designers decided to make u-Boot load the kernel image directly rather than using an uImage. It actually looks like there is a static uImage compiled in, and it just fudges it while booting. The main problem with this is that we don't have a very good way to make sure sysupgrade is dealing with a good image. I made it just check for an LZMA header, which is better than nothing.
This, by the way, is also why support in trunk was tricky. The mtd split code used to determine the rootfs partition boundaries fails without a way to determine where the compressed kernel image ends. We enabled an existing LZMA mtdsplit parser that checks for a valid LZMA header on boot, and looks for the rootfs at the beginning of an erase block. This allows a dynamic partition layout, although slightly less space-efficient than boards with an uImage header; up to 64k is wasted aligning to an erase block.
I thought for a long time that there was no way to drop into the u-boot console. It turns out that after triggering the HTTP recovery mechanism (hold down reset or the Esc key while powering up the device), you can hit 'q' to drop into the console. From there, I could load images over TFTP as I could on the AR725W. Note that there is no u-boot environment stored on flash, so you will likely have to set the serverip variable every time (or configure an alias on your TFTP server) to match your set-up. Also note that it can load standard u-boot images.