iBrickr was an application from Nate True. It was a jailbreak for iPhone OS 1.0.x, which utilized Restore Mode for the jailbreak. It was able to install PXL packages and custom ringtones. Version 0.9 introduced a feature to guide the user through a 1.1.1 to 1.0.2 downgrade.
iBrickr was later retooled for the initial 1.1.3 jailbreak, excluding the aforementioned features. This implementation of the Soft Upgrade jailbreak method required a jailbroken installation of iPhone OS 1.1.1 or 1.1.2 on an iPhone. Nate True was kicked out of the iPhone Dev Team after its release.