Problem configuring touchscreen for Raspberry Pi

Question

I want to use this 3.5" adafruit touchscreen, so I followed this tutorial

I ran the following commands from the link :

curl -SLs https://apt.adafruit.com/add | sudo bash
sudo apt-get install raspberrypi-bootloader
sudo apt-get install adafruit-pitft-helper
sudo adafruit-pitft-helper -t 28r

When rebooting I get just a part of the touchscreen that is displaying Raspbian and I want it fullscreen.

I don't know firstly that I need a tutorial for 3.5 inch and not 2.8 inch so what I did I ran this command again with a little change because I'm using 3.5 inch:

sudo adafruit-pitft-helper -t 35r

Another change that I made is to remove the adafruit duplicate in /boot/config.txt, and now after rebooting the only thing I get is a big white screen.

Update: this what I removed

# --- added by adafruit-pitft-helper Fri Aug  7 16:06:03 UTC 2015 ---
[pi1] 
device_tree=bcm2708-rpi-b-plus.dtb 
[pi2]   device_tree=bcm2709-rpi-2-b.dtb [all]
 dtparam=spi=on
 dtparam=i2c1=on
 dtparam=i2c_arm=on
 dtoverlay=pitft28r,rotate=90,speed=32000000,fps=20
# --- end adafruit-pitft-helper Fri Aug  7 16:06:03 UTC 2015 ---

I got 2 section like described with just the difference in one line

 dtoverlay=pitft28r,rotate=90,speed=32000000,fps=20
 dtoverlay=pitft35r,rotate=90,speed=42000000,fps=20

So I removed the first section !!!

I have ran all commands again either for 2.8, or 3.5 but that hasn't changed anything.

Any suggestions will be appreciated :) thanks