if you have installed yellowsn0w, rebooted and tried switching ON/OFF Airplane Mode many times and still got no signal, then this script might help.

Before proceeding, I assume you've:
1. upgraded your iphone to firmware v2.2 with itunes
2. activated and jailbroke your iphone with pwntools or quickpwn
3. installed mobile terminal
4. installed yellowsn0w (I personally prefer 0.94 although 0.95 is the latest version)

How to use it:
1. copy ysHelper.sh to /var/mobile/ directory of your iPhone
2. open terminal and change user to root by typing: su
(alpine is the default password)
3. then type: bash /var/mobile/ysHelper.sh
4. wait till the script finishes, go to Settings and switch ON/OFF Airplane Mode
5. God bless you

where do i find the file ysHelper.sh ? Please help me out

click on the "script" and download should begin

lit bit breifing required on how to

open terminal and change user to root by typing: su
(alpine is the default password)
3. then type: /var/mobile/ysHelper.sh

in terminal just type this "su" (without quote)
when asked for password, type "alpine"

It says permission denied. Do i have too set a permission on the file?

first you need to become "root" user before executing ysHelper.sh

yes i did put the exact user name and password in the mobile terminal

still not working for me on one set of no service

although i have unlocked 10 pcs till yet

but this set um talking about is no service

you need to give it executable persmissons.

go to mobile terminal

su root

chmod 777 /var/mobile/ysHelper.sh

All it does is restart your yellowsn0w and makes you wait 60 seconds.