Originally Posted by rastik
Can I do dd directly to /dev/mmcblk0p1?
It depends on where you want do dd from.
If you have a serial or usb SSH connection to the kindle while booted from the mmcblk0p2 diag partition, then you can dd a backup copy from /mnt/us onto /dev/mmcblk0p1.
You can also dd from a network connection by piping through netcat (nc), where netcat on your host PC sends the image file over to the kindle, and netcat listening on your kindle receives the image and pipes it to dd, which copies it to /dev/mmcblk0p1.
Personally, I think using an image file on the USB drive at /mnt/us would be easier.
Do not dd to the partition that you booted your kindle from.
If you cannot boot from with the diag or the main partition, things get a little more complicated, and how you do this depends on your kindle model, and what is wrong with it. You probably need to boot to the boot loader using the serial port connection, and then rewrite the main partition by sending the image file over the serial connection using XMODEM or YMODEM protocol. This requires some level of technical expertise and you may need to ask for additional assistance.
On newer Kindle models, new methods have been discovered that use the USB port instead of the serial port. Check out the wiki pages for more info, and other threads in this forum.