Leapster Explorer: Emerald Boot
Emerald Boot is the name of the boot loader that comes installed on the Leapster Explorer. This is the software that takes care of getting the CPU up and running, and loads the kernel for execution.
LeapFrog have made no provisions to upgrade Emerald Boot on the Leapster Explorer. The only way to install a different version, is to flash it to the NOR storage yourself. The Emerald Boot source code is included in the LeapFrog releases. To get the source, download the LF-Linux-* archive of the release you desire to use.
Explorer Sources (LF-Linux-6905-20100610-0915.tar.gz)
Explorer Sources (LF-Linux-8291-20101026-1425.tar.gz)
File:Emerald-boot-supplement v1-1-46.tar.gz UART Boot Patch V1.1.46]
LeapPad Explorer Sources (LF-Linux-2503-20110602-1237.tar.gz)
File:Emerald-boot-supplement v2.0.2.tar.gz UART/AutoSD0 Boot Patch V2.0.2
LeapPad Explorer Sources (LF-Linux-2826-20111215-1417.tar.gz)
File:Emerald-boot-supplement v2.2.2.tar.gz NAND, Didj, UART Patch V2.2.2
While strictly speaking UART booting of Emerald Boot is not possible on the Pollux because of the file size, and hardware restrictions. But if you are handy with a soldering iron, the hardware restrictions can be dealt with, and through the use of a helper program, the boot loader can be uploaded and ran, in a very similar fashion as UART booting. Making testing non-destructive and a lot easier.