1) I use throttle kill programs, really I do. But the TK toggle on this radio is both huge and "exposed on a corner" just asking to be accidentally bumped off at just the wrong moment. In my experience, I found that switch being flipped more often than the throttle stick being bumped, a couple times (before sticky TK) even activating the motor DESPITE the TK program. So, simply cut down the toggle arm to be a more reasonable length. I didn't do that; I waited until the switch broke off, and replaced the entire giant toggle for a smaller and more durable one. I use micro-toggles measuring about 1cm, which prevents accidentally switching it on with a "brush" of the fingers, for this and the two cutoffs below.
2) "Everyone knows" this one, but ER9x wonderfully corrects the left and right arrow buttons. Some of the manuals mention you can reverse the physical buttons to match, but some people have been confused to find their radio has the four buttons bound to a circle of plastic. Yes, you break the two relevant keys off of the plastic "tree" and put them back into the face the right way. They do hold just fine that way, so I'm not sure why they are stuck to the tree either.
3) If you haven't flashed ER9X (why are you here???) or just want to QUICKLY toggle the sound, you can install a small switch to break the piezo speaker's wire. Instant temporary silence without having to change the ER9X menu setting. I originally did this based on the BEEP!-OEM-BEEP!-firmware-BEEP!-that-BEEP!-won't-BEEP!-shutup!, but it's been nice post-ER9X as well for quick adjustments.
4) If you have the HK Backlight, and it works like mine, it's a HOG on battery life. It's really trival to break the power wire going to the board and put in another tiny switch.
4B) While you're there, stick 6" of a white LED strip to the back of your radio, and wire that (on it's own switch) into with the backlight power leads -- it's surprising how often you want a good worklight at the field...
5) I've gotten pretty good with "conventions" in my programming lately, so the same switches are always flaps or gear or VT across all my models with those features. But, it's still surprisingly helpful to take a bit of nailpolish/rubber dip/paint and put colored caps over many of the switches. Yes, electronic stores sell rubber caps, but I find they seldom fit as well as I like and fall off, while paint sticks. Once done, the BRIGHT RED switch is unmistakably the throttle kill, the GREEN switch is unmistakably the "failsafe" mode switch, YELLOW for flaps, etc... As your programs and features get more complicated, it gets harder to remember what switch did what (where IS the "afterburner" switch labeled? Oh, it's the orange one...). Sure, your radio might look a little more christmas-tree like, but you won't crash while looking for the gear...
6) One mod I haven't done myself, but can understand : If you fly much at night, the backlight isn't enough for full control. One fellow I know put TINY leds at each end of the sticks, switches, and pots as orientation lights.... even in the dark, you can quickly locate each switch. A lot of cars have a seemingly "do nothing" light like this on the sunroof controls, so it's not a new idea, just a new application of orientation markers. For me, too dark to find the switches is probably too dark to fly the plane, but it looks cool...
-Gyro
