[dfox]

The amount of bits you need to modify is not “one byte” but the same as the degree of used polynomial.

And producing two strings with same CRC is trivial to the extent that it is how you are originally supposed to use the algorithm. Notice that CRC-32 of every valid ISO9660 filesystem is 0xffffffff ;)

[enedil]

Yes, sorry for the lack of scrupulosity. Of course, it might happen it suffices to change one byte, especially that this byte can be at any position.