urgent help!!! 3g wont start up:(

[172lover]

hi fellas i was at my friends phone and i'd seen that cydia needed 4 updates.

so i clicked uptate.after it installed them it was saying "waithing to reload" or something and it just turned off.

so now it turns onto the apple logo.then it goes to apple logo with a circle going around.then restarts and does the same thing again

its a 3g iphone jailbroken/unlocked also the home button is broken.....

tried
plugging into a wall charger and holding tthe power button
plugging it into the computer
letting the battery die(not fully.only to were it says plug in)
plugging it into the computer and starting blackra1n


please help asap:dapprove:

 

[adamlstr]

If the home button is broken then you won't be able to do anything at all ?

Re-jailbreak, update, unlock etc, will all need recovery mode IIRC.

 

[172lover]

right kinda fixed it :/
swap the motherboard from a 3g with a cracked screen i had lying around.
then restored it to 3.1.3-swaped back broken screen to do dfu mode-then swap back the working screen

should i stay at 3.1.3 or go to 4.X?
the phone NEEDS to be unlockable do!!!
thanks

edit

is the slowness gone from the 4.0 updates for the 3g?