Rating:

Debug the program in QEMU, reverse the protocol, exploit an uninitialized variable using your knowledge of the SPARC ISA.

https://starfleetcadet75.github.io/posts/hackasat-2020-sun-on-my-sat/

Original writeup (https://starfleetcadet75.github.io/posts/hackasat-2020-sun-on-my-sat/).