[Thunderbolt Q&A, Help & Troubleshooting] temp@flawlessangel.com:
Want to save power when WiFi Tethering... try WiFi TXpower. You can find it here:

https://play.google.com/store/apps/details?id=rubberbibpepper.WiFiTxPower

Solution for missing IWCONFIG file:

1. Download the first attachment "iwconfig.txt" (default save location is '/mnt/sdcard/download')

3. Open 'File Manager'

a. Select: 'Menu' -> 'More' -> 'Settings' -> scroll down paste 'donate' (which you should do!)

b. Select: Mark Yes for both checkbox options of "Root Explorer" & "Mount System Folders"

3. Navigate your path over to '/mnt/sdcard/download' and find & rename the file "iwconfig.txt" to 'iwconfig'

4. COPY the file, and navigate your path over to '/system/xbin' and PASTE the file. It may say it wasn't pasted, but scroll down and the file will be there.

5. Launch busybox 'terminal emulator' and type these two commands:

# su

# chmod 755 /system/xbin/iwconfig

6. Boot up WiFi TXpower and verify that the iwconfig error message is gone, and that you do not get a 'iwconfig' permissions error. You should see "iwconfig" and "eth0" titles and all the signal and power stats listed in the app. Lower numbers, less range, and greater batter life.

7. Enjoy! If this has helped you, please hit the "Thanks" button below.

Backstory:

Problem is, this app needs a file 'iwconfig' to be installed in '/system/xbin' and this directory is R/O (read-only, write protected). There are a few ways to do this;

adb push to install the file

Find an APP that will install iwconfig for you

Symlink the file if its somewhere else

Copy & Paste File yourself

I'm old school, so I like to have a hard copy of the file anywhere its needed, and at 30.4 KB, who cares. So following the 80% help link below, I downloaded the 'iwconfig.tar' file, extracted the internal file, and started trying to copy it into '/system/xbin'. From this same site, I used fragments of commands in the busybox 'terminal emulator' to finish the install after the file was copied into the directory. I used '# chmod 755' to set the permissions on the new file, so WiFi TXpower could use it.

"Quoted from:

# su

# cd /mnt/sdcard/download — (this assumes the download location of the file)

# tar –xf iwconfig.tar — (this was to extract the single file from inside the tar file)

#

mount –o rw,remount /system

— (I couldn't get this command to work, but you can try next line below instead)

# mount -o remount,rw -t yaffs2 /system /system — ccdreadcc line of code, that looks like it would work, I received no terminal emulator errors when attempting.

# cp iwconfig /system/xbin — (Above didn't work, so I copy & paste this file in 'File Manager' as I couldn't get 'Root Explorer' to do it, it wouldn't R/W '/system')

# chmod 755 /system/xbin/iwconfig — (You will need this later to correctly set permissions on 'iwconfig', if you don't you will get a "permission denied" error in the WiFi TXpower App)

"

Helpful Links:

80% Help to figure this out, and will be quoting useful parts to solution:

http://jhanford.wordpress.com/2011/10/03/lowering-wi-fi-transmit-power-in-android/

20% Starting and finishing information for solution:

http://xdaforums.com/showthread.php?t=1209251