I am doing a bit off research on exploiting mips embedded applications and I am in a situation where I am able to trigger a buffer overflow, effectively being able redirect execution to any location in memory. There are restrictions however; the memory address I return to and any shellcode I use has to be UTF-8 compatible. This is because the payload has to be stored in an ID3 tag (metadata of an mp3 file).
Since this is mips, I have not come across any encoders that can support creating UTF-8 or alphanumeric shellcode. I am now wondering if this is the case because writing an encoder or shellcode for this architecture is not feasible?