It’s become more common to have the EDID stored in an I2C device that is part of the main silicon (because HDMI requires I2C devices anyway for HDCP and HDMI 2.

It’s become more common to have the EDID stored in an I2C device that is part of the main silicon (because HDMI requires I2C devices anyway for HDCP and HDMI 2.0 SCDC support), but well designed monitors with an I2C PROM for the EDID have the write-protect pin of the PROM asserted to prevent accidental mishaps by tools like this… or by intentionally malicious tools.