Bad hash

When using Open Firmware to copy a new OS from a USB storage stick to the NAND FLASH or SD card, the process might stop and display the message:

Bad hash for eblock# <some number>

The usual cause is a bad USB stick that reads back different data from what you tried to write to it.

The solution is to use a different USB stick. Be sure to copy the files onto the new stick from a known good source - don't copy them from the bad stick to the new one, because that will just move the bad data to the new stick.

You can check the data on the USB stick before using it to update a laptop. Here is one way:

• Insert the USB stick in a laptop and start the Terminal activity)

 $ sudo mount /dev/sda1 /mnt
 $ md5sum /mnt/per703-4.img
 f8dcd6b011c6d54f8d09fac3fe155104 /mnt/per703-4.img

• Compare the result with the contents of the corresponding ".md5" file (for example per703-4.img.md5) in the download directory.