@Dexmaster: That's... not what the OP was asking? That's just to update the jailbreak on previously jailbroken devices running FW 5.6, not to downgrade it [plus, there's no JB version requirement]. (Although, granted, a jailbroken device potentially allows downgrading through diags, but it's NOT for the faint of heart).
EDIT: ... and I just realized you were answering @ElRudi, my bad.

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