I have been reading about the issues (lost drone: OTG cable not supported, fly away etc)  with the Spark Fly more Combo that I am considering  returning this package and not risk the frustration and headaches with the DJI - Spark.  The reviews looked good, but the issues that users are having far outweighs the ease of use touted by the reviews of  this rather expensive toy.  I have had 2 very short flights in my back yard no more than 10 feet high and in beginner mode and keep getting "Weak Image Transmission Signal" error message.  I am very disappointed with this toy and will not recommend it to a prospective buyer.

slyd,
If were using the OTG cable for your 2 flights, then I would suggest you unplug it and fly it as it was designed (using WiFi) before you completely give up on it.  If you try it this way and still have problems at 10 ft away in beginner mode, then you have a right to be disappointed in the product.  

I am using an iphone and have no issues with OTG.  I have flown as far as 1KM and not lost image

I used to fly using the supported wifi method for image transmission and it would be hit and miss depending on distance and what wifi channel I used (you can select them).  I believe 2.4ghz is better for distance, 5.8hz for bandwidth.

I am concerned about fly aways as i've been reading about them too, but my experience so far has been excellent.  It has  been an awesome device for me.

Flying Spark is a rush!!! You have to be like Evil Knivel to turn this damn hung on. But I haven’t been able to fly in for few days and already missing the start up sounds and buzz sound of Spark.

Like the other post says “wise up”
First. Learn as much as possible. Kloo Gee has good videos and advise watch them and listen to his advice. Remember that Spark is designed to be used with WiFi and need at least 11 satellites. Buildings, power cables and other WiFi devices are Sparks enemy stay away from them. Fly at VLOS. Fly is wide open areas. Best shoots are close ups not 500 m away. And remember is smell drone with limited capability. If you want to push it be sure and safe. And soon you become inseparable.

Hi, sir. When you get weak transmission message, please ensure that your drone flies in a place without interference. Here are some tips:
1. I would recommend you enter wifi setting and check if most of the channels are green.
2.Please turn off the bluetooth devices around your spark.
3. I would recommend you change a mobile device for further check.
4. Do not shield the antenna of RC

To all that replied:
Please excuse the delay in replying.  The weather has been dreadful and I have not been able to fly the Spark.
I am a member of a Model Airplane club  with an excellant flying field and will try the Spark as soon as  weather permitts.  Have many years of experiance with model airplanes, helicopters and also racing quads.