How the SFP Wizard unlocks modules (part-number database plus brute force) and why not to downgrade the firmware
Reverse-engineering notes on the SFP Wizard: it reads a module's part number (page A0h bytes 40-55), looks it up in an embedded password database and sends the matching unlock password, falling back to brute force when unmatched. It traces the firmware evolution: v1.0.5 tried only the first database password with no verification (so failures looked like successes), v1.0.10/1.1.0 added marker-cell XOR verification and brute force, and v1.1.3+ tries all matches plus all writable passwords.
- Transceivers: locked SFP modules
- Form factor: SFP
Symptoms / messages:
module stops working after firmware update (community complaint)
silent unlock failure on old firmware
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Comments 1
Do not downgrade: the old v1.0.5 lacked verification and only masked failures, and it removed brute force. Newer firmware verifies the unlock and tries more passwords, so apparent regressions are usually old firmware hiding real incompatibilities.