f3fix

Fix fake flash capacity

$ f3fix --last-sec [size] [/dev/sdb]

$ f3fix --last-sec $(f3probe --destructive [/dev/sdb] | grep 'last usable sector')

$ f3fix --last-sec [1953125] [/dev/sdb]

f3fix [options] device

f3fix creates a partition that matches the real capacity of a fake flash drive. It's part of the F3 (Fight Flash Fraud) toolkit and is used after f3probe identifies a counterfeit drive's actual size.
Fake flash drives report larger capacities than they actually have, causing data loss. f3fix creates a partition limited to the real usable space, preventing writes beyond the actual storage capacity.
The tool modifies the partition table to reflect true capacity, making the device safely usable at its real size.

DEVICE

Block device to fix (e.g., /dev/sdb).

Set last usable sector number.

Display help information.

Requires root privileges. Destroys existing partition table. Use only after f3probe identifies real capacity. Device must be unmounted.

f3fix is part of the F3 (Fight Flash Fraud) project created to combat counterfeit flash storage. The toolkit helps identify and safely use fake capacity drives that are common in online marketplaces.

f3probe(1), f3read(1), fdisk(1)