"To do some work to make it universal" = code change = thrown hash (the signature which requires the Apple key to create, and proves the software hasn't been ta

"To do some work to make it universal" = code change = thrown hash (the signature which requires the Apple key to create, and proves the software hasn't been tampered with, will be broken/no longer valid) Cryptographic hashes like SHA and AES are designed for "dispersion" meaning, in the idea case, flipping only one bit of the input leads to a 50% probability of every single bit in the hash flipping. So while it's theoretically possible to make a change to the code, and find a way to insert that change that both (1) does the same thing and (2) hashes the same way as the original build, it's probably beyond the realm of what even a motivated attacker could do today.