When I first got my new HTC EVO 3D, after taking some 3D pictures and checking out Phereo 3D, I noticed the capacitive buttons were pretty damn bright.
Back in the HTC EVO 4G days, the capacitive buttons (you know, those Home, Menu, Back, Search buttons below the screen) would light up, but it was never a distraction. However, an EVO 3D in a dark room has some distracting capacitive buttons.
Now, you may be thinking that I'm being a little picky. But now that EVO user freeza has come up with a pretty simple fix for my issue, I feel entitled to be.
Like I just said, this is an easy fix; there are multiple methods as well. You can do it on your phone, flash a .zip, or rebuild your ramdisk (if you're brave). The only requirement is that you are rooted. If you are tweaking your ramdisk and have HBOOT 1.50, you will need to use Flash GUI or the advanced methods to flash the new boot.img – but this method is only for really advanced users.
If you want dimmer capacitive lights, follow the tutorial after the break.
Method 1: Terminal Emulator or ADB
echo 2 > /sys/devices/platform/leds-pm8058/leds/button-backlight/currents
Here's what freeza had to say about the settings: "After tinkering for a bit, I've found that 2 is the dimmest it'll go. 1 turns them off, or makes them so dim that I can't tell between them being turned off or not."
This is most likely the easiest method.
Method 2: Flashable .zip method
If you know how to flash a .zip, this method may be perfect for you. However, your ROM must have init.d scripts enabled; luckily, most ROMs have these enabled by default.
You can find the flashable .zip in the thread that is linked at the bottom of this article.
If the first method scares you, this is a good place to start.
Method 3: ROM Developers and advanced users only
Decompiling the boot.img that comes with your ROM isn't that hard to do. Hell, with something like dsixda's HTC Android Kitchen, decompiling your boot.img is easier than flashing a boot.img on HBOOT 1.50 (before Flash GUI).
After decompiling the boot.img, you will find a file called bootcomplete.rc. Then insert the line of code from Method 1 into this file.
After you have completed your method of choice
Enjoy dimmed lights![xda-developers]