What is a "Userland" Jailbreak?

[CaptainChaos]

Great read. I was wondering about this myself!

[rocky5]

cool i was wondering this to, so basically its a Softmod (old Xbox) patches the kernel in memory to bypass signatures and give root access.

Kernel loads and then the softmod starts patches ram addresses then the dash loads (springboard)

but this requires some way of crashing the phone to write to the memory (that's how its pants easy to fix)

[ramicio]

Are the non-userland jailbreaks done for the time being for certain devices (did Apple patch them?)? It seems to me it's a better and permanent alternative.

[Utente]

@ramicio
I'm afraid I didn't fully understand your question. Anyway, non-userland jailbreaks are indeed better than userland ones; and of course more durable, because they exploit some vulnerability in the code (such as iboot) "burned" on the ROM. The code "burned" on a ROM cannot be changed by a firmware updgrade or, in some way, remotely, but it's modifiable only through the physical substitution (or reprogramming) of the intrested memory chip. Whereas userland jailbreaks, since they depend on firmware code's vulnerabilities, can be made harmless with a firmware upgrade.

Though, userland jailbreaks have 2 big advantages: they're cross-platform (that is, do not depend on the idevice's hardware), as @eserfeliz remarked a few posts earlier, and they don't require a low level vulnerability (which is quite hard to discover and exploit). And, take for instance the spirit port on iphone 4 (coming soon), even though userland JBs are easier to patch, apple doesn't always succeed in doing it. Slightly changing the exploit code it's sometimes enough to have it working again on a new firmware version.

[Taizjon]

@H3x.:Jailbreakme.com is back
thanks to @comex to jailbreak iOS 3.1.2-4.0.1 on iPod Touch & iPhone 3G/3GS/4 (Yes the iPhone 4) and 3.2-3.2.1 on iPad!!!