Transceiver EEPROM Flasher?

Anyone ever try one of these cheap flashers for reading/writing transceiver EEPROMs? Do they work?
We sometimes run into odd ducks in the field that are picky about transceiver compatibility, and it would be really useful to just have some spare generic transcievers on-hand and then flash them to whatever brand as needed on the spot. But only if it actually works. Anyone ever do this?

e.g. 01: Fiber Mall EEPROM Programmer Box Supports SFP/SFP+/XFP/SFP28/QSFP+/QSFP28 Transceivers & DAC/AOC Cables

e.g. 02: Cloud Programmer for SFP/XFP/QSFP Optics | GIGALIGHT