View source for IOS16

{{Infobox IOS
| initialRelease = [[Wii Backup Disc]]
| update = [[4.0]]
| version = v512
| type = special
| status = private
| stubvariant = [[4.0]]
}}
'''IOS16''' was an [[IOS]] installed and used exclusively by the [[Wii Backup Disc]]. When Nintendo went to fix the [[signing bug]] in all versions of IOS, they didn't think to release an updated version of IOS16, since it was never publicly distributed, and the "Finalize Repair" option in the Wii Backup Disc deletes IOS16 before ejecting the disc, so it was not installed on post-repair consoles either.

After that update, IOS16 was left as the one last IOS with the unfixed signing bug. It was then unofficially released and used to downgrade the System Menu prior to the [[4.0]] update, primarily to assist in piracy.

One strange property of IOS16 is that it still works on [[RVL-CPU-20]], which made it a convenient target to downgrade other IOSes, although legal methods to downgrade were eventually released, making it simpler.

IOS16v257 has the same build tag as [[IOS14]]v257 and [[IOS15]]v257, and was built by the same builder, but it is 52 bytes smaller.

In addition to being stubbed, [[System Menu 4.0]] refuses to boot any disc set to use IOS16, printing the message <code>This must be a backup disk</code>.