How can i update my iOs if i forgotten my passcode?

You can't. How were you using your iPad mini if you didn't know the passcode to open it?

If you can't update or restore your iPhone, iPad, or iPod touch - Apple Support

deggie *TOLD You how* with the link he gave you... I'll help you out even more... here is what is IN the article linked !!

If you can't update or restore your iPhone, iPad, or iPod touch

You can put your iOS device into recovery mode, then restore it using iTunes.

Use recovery mode

You might need to use recovery mode to restore your device in these cases:

• iTunes doesn't recognize your device or says it's in recovery mode.
• You see the Apple logo onscreen for several minutes with no progress bar.
• You see the Connect to iTunes screen.

Learn what to do if you see the progress bar

onscreen for several minutes.

To put your device into recovery mode, follow these steps:

1. Turn off your device and leave it off.
2. Plug in your device's USB cable to a computer with iTunes.
3. Hold down the Home button on your device as you connect the USB cable. Keep holding down the Home button until you see the Connect to iTunes screen.
   
4. When you see this screen, release the Home button. If you don't see this screen, try steps 1 through 3 again.

When your device is connected, iTunes will open. You'll see a message saying that iTunes has detected an iPhone, iPad, or iPod touch in recovery mode.

Use iTunes to restore your device. Restoring in recovery mode will erase your device. If you previously synced with iTunes or iCloud, you might be able to restore from your backup.

Get more help

Learn what to do if you don't see your device in iTunes for OS X, or in iTunes for Windows.

If you put your device into recovery mode by mistake, restart it. Or you can wait 15 minutes and your device will exit recovery mode by itself.

Last Modified: Feb 20, 2015

Find someone with a computer and iTunes. Or go to an Apple store. You will lose everything on the phone. Purchased items can be downloaded again after the restore of your phone to factory condition.