In the field of aerospace applications, a bootloader, aiming to satisfy the rapid development and iteration of the applications, is needed to reconstruct different applications and ensure its high reliability. Based on the SPARC architecture, this study designs and implements a booloader, which cannot only boot applications automatically according to the bootflag, but also can reconstruct or boot a special application under the control of the ground command. Also, the three redundant architecture, rebound wall, EDAC protection, and other reliability measures have been taken to ensure that the most software failure can be restored. Finally, we test the bootloader on the computer module, and the results have achieved the desired purpose.