This is critical. The A11K stores your IMEI numbers (network identity) in the NVRAM partition. Flashing custom ROMs can wipe this. If you lose your IMEI, you cannot make calls.
Go to Settings > About Phone > Tap "Build Number" 7 times. oppo a11k custom rom
Do not attempt. You will turn your phone into an expensive paperweight. This is critical
A custom recovery replaces the stock recovery menu, allowing you to wipe partitions and flash custom software zip files. If you lose your IMEI, you cannot make calls
The OPPO A11K may be a budget device, but it has untapped potential waiting to be unleashed through custom ROMs. While the process is more complex than on mainstream flagship phones — primarily due to OPPO’s bootloader restrictions — dedicated developer communities have built the necessary tools and resources.
The bare minimum, completely stripped-down version of Android for maximum speed and lowest RAM usage. 2. Ported ROMs