The i2cdetect doesn't work properly but you can still use the i2c on omega2. if you are looking for sample code to use MCP23017 you can find them over here MCP23017 python lib
I have been using Omega 2 i2c to control relay, read sensors and ADC without any problems.
Hope this helps.
@Lazar-Demin For myself, I am running a power dock in stationary mode with no battery connected, however the LED is flashing low battery warning (not erratically). I have tried a 2A wall wart with the same results. The power dock and Omega, all LED's turn off.
@luz Maybe your system does use the environment; I've never seen it anything but blank and recall that trying to set things there didn't work for me, but I'm running a patched mediatek u-boot not an onion one.
It really depends what your demands are regarding WiFi.
If you can live with mediocre WiFi performance (for now), then use LEDE. You can build everything that is on the original Omega FW that way, except for the wifi driver. Onion uses a proprietary driver they can't publish, stock LEDE uses the fully open sourced, but not yet fully fine tuned, mt76 driver.
For all of my Omega2 based applications I built my own distro / FW image from LEDE, tailored to the use case. There is a learning curve to LEDE, but once you get a feel for it, it's a really nicely organized distro builder for tiny platforms.
For example you can start here, read about LEDE on their site and of course search this forum, which has a lot about custom FW builds.
In case anyone stumbled upon this issue or something related to this.
Since I do not have a linux machine, I decided to spin up a cheap 1cpu, 512MB ram, $5 digital ocean droplet to setup my toolchain and compile some code for the onion. The above issue occurred on a fresh ubuntu 16 and ubuntu 17 droplet. A friend did some googling and pointed out that these type of issues could be memory related and he was spot on.
After setting up 2GB swap space using this guide: Adding Space on Ubuntu the compile has completed successfully on both Ubuntu 16 and 17.
Hope this helps someone experiencing this frustration.
With regard to CC0 vs GPL, it may (not sure) be possible that you can incorporate CC0 code into a GPL project and license the result as GPL. However is it definitely prohibited to use GPL code literally or via derivation in something licensed CC0. That is because a CC0 offering of a combined result would not preserve the irrevocable obligation to make a GPL license grant for derivative works of your derivative, hence such use cannot be permitted.
With regard to documentation, since you are aiming for bare metal, the culprit for your specific difficulty is more Mediatek than Onion. I'm not sure if the Onion boards are perfectly documented, but that would be easy to reverse engineer, and besides, they'd be a bad choice of MT7688 platform, since you have access to neither the flash chip nor the JTAG pins without a very tricky operation of removing the shield can.
You need to explain exactly what you mean by "will not provide Internet".
I don't usually use Onion's software stack on the MT7688, but I'd be a bit surprised if it rejects an access point merely for not having a link to the outside world, chances are your problem is more fundamental.
I have a program that reads from a usb cdc device (/dev/ttyACM0). It's basically a serial port. It runs fine anywhere else, but when run in Omega2 or Omega2+, it dies with the message:
do_page_fault(): sending SIGSEGV to nowd for invalid read access from 7faae0000,0,0,0,0,0,0,0,
[ 228.111736] epc = 0040106b in0,0,0,0,0,0,0,0, nowd[400000+2000]0,0,0,0,0,0,0,0,
[ 228.119167] ra = 00401079 in0,0,0,0,0,0,0,0, nowd[400000+2000]0,0,0,0,0,0,0,0,
(nowd) is my program.
Google do_page_fault() and SIGSEV results in a lot of hits. They all point to Omega2, LEDE, kernel 4.1.x. People have reported it happening to dnsmasq, fast-gpio, etc., some said it was fixed but no one pointed out what the problem was.
There was a similar thread that hinted DEVMEM not being configured in the kernel. So I built a LEDE firmware with DEVMEM and DEVKMEM enabled. No joy.
Can someone from Onion team shed a light on this issue?