Hopefully, someone else can answer your wifi question, but there's also an alternate method you can use, if you have a Windows computer and the ability to read/write to SD cards (USB adapters can be purchased cheaply, like this one: https://www.amazon.com/IOGEAR-MicroSD...D/dp/B0046TJG1U),
Pull the SD card from your iFly, connect it to your computer, and run iFly Connect to perform the update. It's faster than using the built-in wifi on the iFly device.
Download and install instructions are here: http://www.iflygps.com/UPDATES/Download-iFly-Connect
I don't use an iFly device anymore, but I used a 700 and a 720 for years. With the 700, I download update packages to a USB thumbdrive and plugged it into the 700 to perform updates. With the 720, I used wifi when I first got it, but when the iFly Connect method was introduced, I switched to that and used it exclusively for years because it was faster and more convenient.