It's likely you are facing one or possibly the combination of two known issues.
One is that because an incompatible 32 megabyte SPI flash was used, accessing the whole of it requires putting it in a mode incompatible with boot, so unless something resets the flash chip when the CPU does, a warm boot will fail. Most other vendors avoided this by operating their 32-megabyte flash in 4-byte address mode all the time (but that would have required different strapping for the 16 meg and 32 meg versions).
Another is that if you have anything connected, say a debug serial port, the data lines itself will keep the MT7688 alive enough that it won't do a clean power on reset . Potentially in this case you have a similar leakage path where an I/O is keeping your flash chip alive enough during the power interruption that it isn't losing the boot-incompatible 4-byte address mode state. Or you could have residual charge on a capacitor.
Thank guys I took a look at the note and ordered a few different units to test.
My preference is really to have 5GHz built into the the Pro or a version of the Pro. Purely from a mechanical point of view, my IoT device exposed the mini-usb port on my case so users can power the device, this would mean I have to also expose the USB-A port with the 5GHz dongle which looks pretty messy and I know users will unplug it or fiddle with it and then complain they have no network connectivity. Alternatively I would need to redesign my case to move the Omega away from the side of my case and use a short mini-usb case mounted port. Either way it's messy.
@Yoh-Yamada You have got an Arduino Dock 2.
There are a few obvious things:
You have plugged an Omega2(+) into the socket of that dock in right direction and right position.
Is your 5V power supply okay?
Is your Omega2(+) able to boot successfully? What about the amber LED?
After a successful boot you must find an Omega-**** WiFi AP among the WiFi networks on your smartphone (too).
Default password is: 12345678
Can you connect to it?
Launch your favorite web browser and type: http://192.168.3.1
Connect to the http://omega-****.local/ site with a smartphone is another story.
For what it's worth, my experience with the 2+ is that it seems to have a slow wifi connection, more precisely it doesn't seem to have a very powerful tx/rx. It was actually causing my wifi AP (Ubiquiti) to switch down to half duplex due to the error rate. I moved the device within a metre of the AP and all my issues were solved.
You may argue that my wifi AP was at fault but I tested on 3 different AP on my network and on a totally different wifi network at my office across town. If I monitor the wifi AP it will randomly switch to half duplex. If switch off the Omega, the AP will never switch to half duplex.
@Max-Mitchell If you have installed the cross-compiler tools, mipsel-openwrt-linux-as is there alongside with mipsel-openwrt-linux-gcc which can also compile inline assembler. This definitely works, as I have programmed the Omega2's DSP coprocessor with SIMD assembler instructions :)