It's very amusing that this kind of legend has persisted! ZFS is notorious for *noticing* when bits flip, something APFS designers claimed was rare given the robustness of Apple hardware.[1][2] What would ZFS on iPhone have looked like? Hard to know, and that certainly wasn't the design center.
Neither here nor there, but DTrace was ported to iPhone--it was shown to me in hushed tones in the back of an auditorium once...
I did early ZFSOnLinux development on hardware that did not have ECC memory. I once had a situation where a bit flip happened in the ARC buffer for libpython.so and all python software started crashing. Initially, I thought I had hit some sort of blizzard bug in ZFS, so I started debugging. At that time, opening a ZFS snapshot would fetch a duplicate from disk into a redundant ARC buffer, so while debugging, I ran cmp on libpython.so between the live copy and a snapshot copy. It showed the exact bit that had flipped. After seeing that and convincing myself the bitflip was not actually on stable storage, I did a reboot, and all was well. Soon afterward, I got a new development machine that had ECC so that I would not waste my time chasing phantom bugs caused by bit flips.