@eureka: Yeah, never really thought about it, but I've always (quite possibly erroneously) assumed using a mounted part (even ro) as an input for dd was a bad idea

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@Alb: The jailbreak and the *kindlet* jailbreak are two *different* things. You'll need both to run ixtab's Font Hack, and you need a jailbroken device to install the Kindlet jailbreak. Check ixtab's doc again

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If you did install *both*, then, yeah, it's probably because something changed in 5.1.1.
The good news seems to be that the jailbreak installed successfully, using the same method as for 5.1.0. You did end up with the 'You are jailbroken' book, yes?