[Mesh] So, about those Meraki Sparky boards

A little drinking at Noisebridge and some poking from JC got me thinking about the Sparky boards. So I came up to Sudo and worked with Marc to figure it out. The TL;DR version: It's an AR2317 and you have a watchdog timer, but it doesn't actually reset the unit. It just posts an interrupt. It turns out GPIO6 is the "pat to stop it resetting" line. So, the details: I first did "help" at the redboot prompt. I found "bdshow", which is the "Atheros board info." RedBoot> bdshow name: Meraki Outdoor 1.0 magic: 35333131 cksum: 2a1b rev: 10 major: 1 minor: 0 pciid: 0013 wlan0: yes 00:18:0a:50:7b:ae wlan1: no 00:00:00:00:00:00 enet0: yes 00:18:0a:50:7b:ae enet1: no 00:00:00:00:00:00 uart0: yes sysled: no, gpio 0 factory: no, gpio 0 serclk: internal cpufreq: calculated 184000000 Hz sysfreq: calculated 92000000 Hz memcap: disabled watchdg: disabled (WARNING: for debugging only!) serialNo: Q2AJYS5XMYZ8 Watchdog Gpio pin: 6 secret number: e2f019a200ee517e30ded15cdbd27ba72f9e30c8 .. hm. Watchdog GPIO pin 6? What's that? After manually checking out the watchdog registers via 'x', we discovered that it would count down to 0 and not reset. So, hm. Maybe the GPIO 6 wire is actually the right thing to pat. And yes, the board doesn't reset when you pat GPIO 6. Board: ap61 RAM: 0x80000000-0x82000000, [0x8003ddd0-0x80fe1000] available FLASH: 0xa8000000 - 0xa87e0000, 128 blocks of 0x00010000 bytes each. == Executing boot script in 2.000 seconds - enter ^C to abort ^C RedBoot> # set direction of gpio6 to out RedBoot> mfill -b 0xb1000098 -l 4 -p 0x00000043 RedBoot> x -b 0xb1000098 B1000098: 00 00 00 43 00 00 00 00 00 00 00 00 00 00 00 03 |...C............| B10000A8: FF EF F7 B9 7D DF 5F FF 00 00 00 00 00 00 00 00 |....}._.........| RedBoot> # pat gpio6 - set it high, then low. RedBoot> mfill -b 0xb1000090 -l 4 -p 0x00000042 RedBoot> mfill -b 0xb1000090 -l 4 -p 0x00000002 .. then I manually did this every minute or so. RedBoot> RedBoot> mfill -b 0xb1000090 -l 4 -p 0x00000042 RedBoot> mfill -b 0xb1000090 -l 4 -p 0x00000002 RedBoot> mfill -b 0xb1000090 -l 4 -p 0x00000042 RedBoot> mfill -b 0xb1000090 -l 4 -p 0x00000002 .. so, the solution here seems to be to "set gpio6 to be output", then "pat it every 60 seconds." -a