Embodiments disclose a firmware upgrade method and apparatus, and a terminal. The method includes: sequentially obtaining first upgrade data and operation instructions in all data blocks in a block differential upgrade package; converting first data into a second upgrade data in an image of an old firmware version according to the operation instruction; and controlling the first upgrade data and the second upgrade data to overwrite a to-be-upgraded data area in the image of the old firmware version. An operation of upgrading to an image of a new firmware version is completed in the image of the old firmware version based on the first upgrade data and the second upgrade data. In addition, in comparison with a conventional differential upgrade package, in the block differential upgrade package, a part or all of data in the conventional differential upgrade package is replaced with an operation instruction.