This is a question that gets asked a lot in support topics and rather than just making a mini tutorial for every support topic, I thought I'd make a mega one to help the newbies. There's more than one method of which I know so I'll be listing them all down here. Method 1: Using Activator Gesture You can set a custom Activator gesture which can send you straight to Safe Mode! Step 1: Download Activator from Cydia if you don't have it already. Step 2: Open Activator settings and choose whether you want the Safe Mode to be triggered Anywhere, At Home Screen, In Application or At Lock Screen. I'm choosing Anywhere. Step 3: Now select your preferred gesture. I will be using Both Press Volume Buttons. Step 4: Scroll all the way down to 'System Actions' and select 'Safe Mode' from the list. Step 5: Close out of Activator settings and do the gesture you just set to send your iDevice into Safe Mode.
Method 2: Using Apps & Tweaks from Cydia Another way to do this is by using some Tweaks from Cydia which are: EasySpring2 (iOS8) BetterPowerDown Pangu App PowerDown Pro PowerDown Gpower Pro (iOS 6) I suggest EasySpring2 since you can set an Activator gesture with it also and make the Power Down menu appear faster. 1. Install EasySpring & Activator from Cydia. 2. Open Activator settings -> Anywhere -> Sleep Button -> Short Hold -> Assign it to EasySpring. 3. Close Activator and hold the volume button for 2 seconds to get the EasySpring menu from where you can reboot, power down, respring & safe mode! Helpful topic: http://iosgods.com/topic/4866-best-tweak-to-use-when-intalling-hacks-or-tweaks/
Method 3: Using Volume Up Button (No Cydia Tweaks) Step 1: Turn your iDevice completely off. Hold the power button and slide to power off. If your iDevice has frozen, hold the Power Button + Home Button for ~10 seconds or until the screen goes black. Step 2: Once the device is completely off, press and hold the Volume Up (+) button then press and hold the Power Button to turn your iDevice on. Keep the Volume Up button pressed meanwhile. Step 3: You can let go of your Volume Up button after ~10 seconds but just to be sure, keep it pressed until you boot back into your Home Screen. Done! You should now be in Safe Mode. Video Tutorial:
How to get out of Safe Mode: To get out of Safe Mode, you can click the "Exit Safe Mode" text at the center of your status bar or you can just turn off and turn on your iDevice normally.