按照慣例沒有這個東西就安裝這個東西

所以: sudo apt-get install uboot-mkimage

結果說沒有找到安裝包，但是提供了替換的安裝包：就是這個 u-boot-tools

Reading package lists... Done

Building dependency tree       
Reading state information... Done
Package uboot-mkimage is not available, but is referred to by another package.
This may mean that the package is missing, has been obsoleted, or
is only available from another source
However the following packages replace it:

  u-boot-tools:i386 u-boot-tools

所以安裝: sudo apt-get install u-boot-tools