OnKey founder Yishi warns that iPhone 11 and earlier models should not be used to store cryptocurrency wallet recovery phrases because hardware vulnerabilities cannot be fixed through iOS updates. Yishi says that even with Airplane Mode enabled, an attacker with access to the device can run code via USB before iOS starts. Yishi recommends that affected users generate a completely new recovery phrase in a trusted environment and transfer their assets. Previously, Yishi recommended using iPhones as cold wallets, but only iPhone 17 and newer models.