Substrate 0.9.5016 fixes a bug introduced with the previous two Substrate releases. Have a look at Saurik’s change log after the break.
From the release notes:
Substrate 0.9.5016 fixes a bug on iOS versions before 4.3 (versions 0.9.5014 and 0.9.5015 caused many devices to spontaneously reboot after installation and then not boot again without first disabling Substrate with volume up).
This is an impressive look at just how well Cydia is designed to be backward compatible with earlier iOS firmware. Many App Store developers have long since dropped support for early iOS versions, but Saurik provides support for even some of the earliest iOS firmware, like iOS 2!
But seriously, who still running his iPhone below iOS 4.3 ?