
iOS 7 was recently jailbroken untethered, and the evasi0n7 jailbreak tool used to jailbreak iOS 7 was recently updated to version 1.0.1.
Currently, Mobile Substrate, the dependency used by many jailbreak tweaks in Cydia, has not yet been updated with support for iOS 7, or for 64-bit iOS devices. This is the reasoning behind needing to re-install Mobile Substrate and then needing to respring every time you reboot your device, and is also the reason that jailbreak tweaks are not working on 64-bit devices like the iPhone 5s and iPad Mini with retina display.
If you have jailbroken your iOS 7 device, whether it’s 32-bit or 64-bit, you should definitely hold off from downloading third-party hacked together versions of Mobile Substrate, or third-party patches for Mobile Substrate intended to make it work correctly on these newer devices.
Why, you ask? Well, first of all, they’re probably not going to make it work correctly.
Saurik recently took to Reddit to respond to a widely used third-party Mobile Substrate patch that claims to "load all tweaks without a reboot or respring" on iOS 7. The patch doesn't fix tweaks for the 64-bit A7 chip, but it does claim to fix Mobile Substrate for iOS 7. If you were thinking about grabbing it, you may want to read Saurik's response about why you shouldn't:
This is horribly dangerous: MSHookFunction is not designed to be used on functions that might actively be running; this makes Substrate get injected into launchd while launchd is loading launch daemons... no one should install this; it doesn't even solve the problem remotely correctly for anything but SpringBoard/backboardd, and will end up leaving you with Substrate having been randomly applied to different background processes.
Saurik notes that he took Christmas Eve and Christmas off from working on things, but that he will be working on them again and should have a fix out soon. A lot of Saurik's recent free time went to updating Cydia for iOS 7.
The best option right now is to just remain patient until Saurik issues an official update for Mobile Substrate.
Sources: Reddit
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