Ok so i've got a spark, on latest firmware.  Trying to get it to be seen within the Go app and it doesn't want to see it. Steps i take

Open App (android. latest app, galaxy s7)
App opens and defaults to Mavic Air on the screen for some reason.  Says disconnected.
Enter device - Activate aircraft - doesnt want to know when scanning barcode - fair enough seems that these barcodes have been printed off pretty badly from what I have read on here.
Connect to aircraft - combo (i have remote) next next  scan barcode (give up)
Connect manually to wifi - connects fine has IP but no internet (expected)
go back to app -- still says disconnected.

what now?

Remote is connected to the aircraft as I can use that to take off etc.

so let's take a step back..
how do you know you have the latest firmware? it's the App telling you that. did you previously connected to the App?
your phone needs to connect to the remote controller WiFi. then the RC connects to Spark. then the App will open up and show you "go fly". is this what you have been doing?
and did you activated your aircraft previously?

Ok so I've tried on my samsung tablet and it seems to connect, although it disconnects a LOT (unusable). (although the remote works fine so there is clearly no issues with that wireless side of things).  Obviously I cannot use OTG cable as DJI have stupidly removed that functionality for us.
Any ideas as this thing is pretty much useless to me right now.

dj_dread Posted at 2018-1-31 14:43
so let's take a step back..
how do you know you have the latest firmware? it's the App telling you that. did you previously connected to the App?
your phone needs to connect to the remote controller WiFi. then the RC connects to Spark. then the App will open up and show you "go fly". is this what you have been doing?

I connected it to my laptop and it checked.
go fly doesnt come up on my phone.  just says disconnected.  
the spark is a used one so cannot activate it, but from what I can see , activating doesnt work anyway as it doesnt scan the barcode properly.

do you see RC WiFi on your phone/tablet? it starts with RC-xxxx

Yes, sorry, I might not have been clear in my  OP, it's connected and says it has an IP but no internet (expected)
Granted this may be an issue with the phone I'll have to investigate that a bit further, but i'm (more than) a little concerned that on my tablet it is just plain terrible and essentially useless with it cutting out constantly and video being very very laggy.

ok. so you can connect your phone/tablet to the RC. when open up the App does it show in the lower left corner "Connected"?
if yes, does it show Go Fly in the lower right?
is your RC connected to Spark? (green LED on RC)

No it says disconnected in the APP.  it doesnt say connected.  It doesnt say go fly.  it says the usual "enter device" option.   yes as i say the remote works fine to the spark. I can use that happily with no issues.  it is specifically the phone to the remote that is the problem.

ok. try to read the manual here: https://www.dji.com/spark/info#downloads
usually, if your phone is connected to the RC, then the App will show "Connected" on the lower left side of your phone screen.
again, you need to chose the RC WiFi on your phone. the "factory" password is 12341234. and the WiFi SSID will start with "RC-something". If it doesn't show like that it means it was changed. in this case, press the power button on your RC for 9 seconds (you will hear 3 beeps). that will restore the RC to factory settings (including WiFI SSID). Then you can pair your phone to the RC using password 12341234.
if this does not work...i'll let the more experienced members here to step in.

Yeah. Needless to say I've already read the manual and I'm pretty IT Literate (it's my job). I get what you're saying but I've done all that and I'm Def "connected".  Thanks for your help.  Fingers crossed that someone experienced can chime in too.

gibbon Posted at 2018-1-31 18:31
Yeah. Needless to say I've already read the manual and I'm pretty IT Literate (it's my job). I get what you're saying but I've done all that and I'm Def "connected".  Thanks for your help.  Fingers crossed that someone experienced can chime in too.

Please try with another device and tell me the colour of your indicator of your RC. Sorry for the mistake. Thanks for reminding.

Are you using the latest firmware?

DJI Elektra Posted at 2018-1-31 19:24
Glad you solve the problem. Have fun with it.

Huh? How did you get that from what I wrote?

SOUNDWAVE439 Posted at 2018-1-31 19:53
Are you using the latest firmware?

Not being funny but that was literally the first thing I wrote

gibbon Posted at 2018-1-31 19:57
Huh? How did you get that from what I wrote?

Yeah, sometimes I also wonder if that's real human behind or just a chatbot.
Anyways, have you tried to reset the Spark?

1. Turn Spark on (one short, followed by long press)
2. Wait till it initializes.... so wait till that lightshow ends
3. Once initialized press the button on battery and hold it for aproximately 9 seconds. After 3 seconds you'll hear one beep from Spark, after 6 seconds it will be 2 beeps and after 9 it will be 3 beeps. Once you hear 3 beeps you're good and you can release the button.
4. Start DJI GO App on your device
5. Select Spark (it will default to Mavic Air but you need to change to your craft type)
6. Tap Find device and proceed as usual.

Please note that Spark can be bound to only one controlling device at the time. So it's either RC or phone. Can't be bound to both simultaneously. So, once you decide to bind it back to RC, you'll have to repeat the procedure above.

I did a factory reset when i connected the spark to my laptop using the app (in the firmware page).  is that the same thing?
Does it automatically know to pair with the remote? cos i didnt have to do anything to get it to talk to that again.

See this post may solve your issues.
https://forum.dji.com/forum.php?mod=viewthread&tid=126591&pid=1459074&page=1&extra=&mobile=2#pid1459074

This is exactly the same situation my spark is going through right now. I have tried the same think as you but nothing. DJI want me to reload DJI assistant 2. Set everything to factory and reload the firmware to see if this is the problem.

I don't know but my dji go4 app can't show live images. In fact i have connected the spark with my phone but it still see disconnect when i go to the live view.