The KK2.0 and relation to gain with flashed ESCs

I've read that flashing escs lets you increase gain. On my tricopter, with 1000kv motors, flashed HK SS escs, 48cm arms, I started flying with firmware v1.6. With some quick tuning I was flying fairly alright with the pitch/roll P gain at around 70(didn't spend too much time tuning, too busy flying :D), everything else stock. After I put on fpv equipment ( HK 800mW 900MHz tx, ccd camera, 460mAh 3s) it became a bit sluggish. So I decided to tune it properly. Set the I gain to zero and began increasing P. It went upto 170 without oscillating. Haven't been able to tune the I gain since.

What exactly is going on, and what allows you to increase gain, if at all? Does it have anything to do with the increased refresh rate, and how high can one go with tuning values?
 

Cyberdactyl

Misfit Multirotor Monkey
I've had amazing good luck with the HK 20A ESCs, then flashing them with the simonK BS N-FET hex.

They are an amazing bargain, and I have to tip my hat to David W for recommending them.

They work outstandingly well. I've now flashed 12 of them. And I have had them pretty hot driving DT750s with 1147 props getting them up around 115F on a hot summer night lifting my laser module and camera (1600+g), and haven't had one fail yet, I can't imagine paying $18 for "something special" and someone to flash it, when you can have similar for $7 plus postage. And of course the initial outlay of the USBasp tool ($5) and whipping up the homemade interface pin array (30min build).