Screen display program upgrading method and system and terminal equipment

The method is suitable for the technical field of program updating. The invention discloses a screen display program upgrading method and system and terminal equipment. The method comprises the following steps: entering a boot loader when a screen display program upgrading instruction is received, and reading the data of an upgrading flag bit stored in a first preset address which is not lost whenthe data stored in the first preset address is powered down; if the data of the upgrade flag bit is matched with the preset upgrade flag, installation a file system of the external storage device, reading an upgrade file from the file system, and writing the read data in the upgrade file into a second preset address; and after the read data in the upgrading file is successfully written into the second preset address, clearing the data in the upgrading flag bit. According to the invention, the upgrading of the screen display program can be realized only by using the external storage device, the operation process is si