A wiped iPhone in airplane mode, kept only for wallet recovery, sounds like the safest place a seed phrase can live. Custody was the barrier.
That assumption fails for a large slice of Apple’s installed base, according to Yishi Wang, founder of hardware wallet maker OneKey. In an October 31 post, Wang argued that anyone keeping recovery words on an iPhone 11 or older holds an expiring assurance, because the flaws that matter sit above the OS.
Two exploits, one permanent gap
The BootROM is the first code an iPhone runs, fused into the processor rather than stored on flash. No update reaches it. Checkm8, disclosed in 2019, covers the iPhone 4S through the iPhone X. Usbliter8, published in June, extends the exposure to Apple’s A12 and A13 silicon: iPhone XS, XR, the whole 11 line and the second-generation SE.
The procedure needs only moments of custody. An attacker forces the handset into device firmware update mode, attaches a custom USB device and runs code before iOS loads. Airplane mode is irrelevant here, because the chain never reaches the network.
A gap is not a compromise
Passcodes, file encryption and the Secure Enclave still stand between an unlocked BootROM and a wallet file. Wang rated the risk serious mainly where people lean on six-digit codes, stale software or weak app passwords.
His framing put more weight on quiet tampering than on remote theft. A phone left in a hotel room is the scenario, and the owner may notice nothing.
For anyone in this position the advice is to abandon the phrase. Fresh addresses generated from the same twelve or twenty-four words still trace back to one exposed key, so a new phrase on trusted hardware is the only exit.
Apple has no patch. No iOS update changes a ROM.
