IOS253

IOS253 is a temporary IOS, created by older versions of "xyzzy", that sometimes remains in the NAND. It can be safely deleted.

The reason for the IOS being there becomes clear when you look at how "xyzzy" used to work. The following is taken from hackmii.com:

Download IOS11 from the Nintendo Update Server
Patch it to remove the MEM2 protection (so the PPC can access all 64MB of it)
Patch it to allow it to delete itself later using ES_DeleteTitle()
Install the hacked IOS11 into IOS253
Reboot into the hacked IOS
Copy the private key structure from the IOS address space into MEM1
Reboot back into a sane IOS
Delete the temporary, hacked IOS
Display the keys on screen
Try to write them to a file on the SD card — keys.txt
Pause for 60 seconds to allow you to copy the keys down using pen and paper,if necessary

Version	Signing bug?	STM Release Exploit?	Notes
v31337	Yes	Yes	Temporary IOS, created by old versions of xyzzy.