I didn't think change the TV mode would help, nevertheless, I will give it a try later. However, I'm thinking to buy the 8Bitdo instead.

https://www.amazon.co.uk/gp/product/B01MEFZKHZ/ref=ox_sc_act_title_1?ie=UTF8&psc=1&smid=A2NB95UVHG1P3I

Anyone has this?

Amazon have increased the prices of some accessories. Cases gone up £4 since I've added them to basket.

I found it was very slow to respond on the fire TV 4k, I was hoping to be able to use it with my phone for vr games but no joy with getting it to pair. it went back as it was pretty useless

You might need to put your TV in game mode.

Is the code FLYER10 applicable to other items too?

could be a faulty controller I haven't experienced any lag on mine...

I bought it for my fire tv stick, primarily for NES emulator, however, there is one second lag, on any emulator even on Fire TV official games, have to return it, as it's useless with this one second lag. Maybe I need to buy the Fire TV 4K, which is much faster than stick.