After flashing, you must boot into OPPO Engineering Mode ( *#8011# or *#36446337# – though often disabled by stock ROM). Using ADB (Android Debug Bridge) while the device is in "Factory Mode" (before setup wizard):
When an employee leaves a company, a student graduates, or a device is sold at auction, the MDM lock often remains. Unlike a simple Google FRP (Factory Reset Protection), an MDM lock is persistent. It survives factory resets and standard firmware flashes because the management profile is injected deep into the OEM partition or the system’s persist partition. oppo a79 5g cph2557 mdm ota remove firmwareby full
The CPH2557 uses a dual-partition scheme (A/B slots) with a dedicated mdm partition (sometimes labeled mdm1 and mdm2 ) or a secured persist block. The standard Android fastboot erase userdata command does not touch these protected areas. Furthermore, OPPO’s ColorOS 13+ has a "rollback protection" feature that checks for MDM tokens during the initial setup wizard. The "Full Firmware" Requirement To truly remove MDM from the CPH2557, you need a Full Firmware package. This is distinct from an "OTA Update.zip" (which only patches existing files) or a "Payload.bin" file (which updates only system/vendor). After flashing, you must boot into OPPO Engineering