MobileRead Forums - View Single Post - Is Das U-Boot on the MMC or some other type of ROM?

asymptote · 10-24-2012, 04:30 PM

Where is Das U-Boot on the Kindle that the ARM processor looks for and boots
Is it safe to erase? Can it be restored?
How can it be backed up/restored? With which tools?
What are the differences between the tools?

Where is Das U-Boot stored? Is it on the main 4GB MMC that contains the Linux filesystems as well as the VFAT "thumb drive" partition? Or is it in some specialized type of boot ROM somewhere else?

I'd like to know how to entirely backup my Kindle Keyboard (Kindle 3) including the bootloader, and I'd like to know how far I'd have to go in erasing things to completely brick the Kindle. I have a 1.8V TTL cable and can access the serial port, so if it's only possible to brick the USB functionality but it can still be reprogrammed with the UART that is fine.

The reason for my asking is that I intend to completely rewrite the Kindle's firmware from the ground up for a personal project involving the eInk display and the serial port. I know I could just the existing bootloader and Linux kernel/drivers, but that isn't what I am interested in doing. I'd like to erase everything and start with a clean slate, but at the same time I don't want to brick my Kindle to the point the reprogramming tools are useless.

Also I'd like to know what the differences are between the various Kindle flashing tools: Freescale ATK, MfgTool, fastboot, k3flasher, etc.

I dumped the first 700mb of the flash filesystem using the ATK. MfgTool didn't seem to have an ability to dump -- only to program. I have not tried fastboot, and k3flasher seems to just be an linux alternative to ATK.

I'd appreciate insight!

10-24-2012, 04:30 PM	#1
asymptote Junior Member Posts: 3 Karma: 1000 Join Date: Oct 2012 Device: Kindle 3	Is Das U-Boot on the MMC or some other type of ROM? Where is Das U-Boot on the Kindle that the ARM processor looks for and boots Is it safe to erase? Can it be restored? How can it be backed up/restored? With which tools? What are the differences between the tools? Where is Das U-Boot stored? Is it on the main 4GB MMC that contains the Linux filesystems as well as the VFAT "thumb drive" partition? Or is it in some specialized type of boot ROM somewhere else? I'd like to know how to entirely backup my Kindle Keyboard (Kindle 3) including the bootloader, and I'd like to know how far I'd have to go in erasing things to completely brick the Kindle. I have a 1.8V TTL cable and can access the serial port, so if it's only possible to brick the USB functionality but it can still be reprogrammed with the UART that is fine. The reason for my asking is that I intend to completely rewrite the Kindle's firmware from the ground up for a personal project involving the eInk display and the serial port. I know I could just the existing bootloader and Linux kernel/drivers, but that isn't what I am interested in doing. I'd like to erase everything and start with a clean slate, but at the same time I don't want to brick my Kindle to the point the reprogramming tools are useless. Also I'd like to know what the differences are between the various Kindle flashing tools: Freescale ATK, MfgTool, fastboot, k3flasher, etc. I dumped the first 700mb of the flash filesystem using the ATK. MfgTool didn't seem to have an ability to dump -- only to program. I have not tried fastboot, and k3flasher seems to just be an linux alternative to ATK. I'd appreciate insight!