h2fmi — NAND storage

Flash driver messages from older iPhones (WMR, h2fmi: sequencer timeouts / NAND status). An iFixit respondent sees a file system or NAND controller problem.

iPhone

NAND / storage controller (older models, e.g. iPhone 5)

Low confidenceVerified sourceNAND storage

First check

Reinstall iOS; if the panic continues, NAND hardware fault.

Sources