Leapster Explorer: Testing Kernels via USB Boot

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The Leapster Explorer includes a USB recovery function, designed to be used in conjunction with LFConnect to recover the Leapster Explorer to a known-working state. We can leverage this USB recovery function to transfer kernels we want to test to the Leapster Explorer without having to do a destructive write of the new kernel to the LX nand (which can be dangerous). The result is an ability to test kernels on Leapster Explorer using USB booting, just like we test kernels using UART or SD kernel booting on the Didj.


USB Booting

CBF File Format

Kernel Configuration

Modify lines 999-1008 of linux2.6/drivers/mtd/nand/lf1000.c as follows to enable mounting of the onboard partitions:

//if (gpio_get_boot_source_config() == SCRATCH_BOOT_SOURCE_USB)
//	base_parts = partition_info_recovery;
//	base_parts_nb = ARRAY_SIZE(partition_info_recovery);
    base_parts = partition_info;
    base_parts_nb = ARRAY_SIZE(partition_info);

You can then build your kernel as you normally would.

The bootloader expects the kernel to be in the Common Boot Format (cbf) LeapFrog included a script in their sources. To create the 'cbf' in the scripts directory, type:

$ make_cbf.py

You now have a kernel ready for USB Booting.