Note: Do not uninstall com.android.shell or com.mediatek.mtklogger or you will soft brick.
adb shell pm uninstall -k --user 0 com.chinamobile.services adb shell pm uninstall -k --user 0 com.mediatek.bluetooth adb shell pm uninstall -k --user 0 com.android.stk china mobile a4s firmware
Before seeking firmware, try a factory reset via recovery (Power + Volume Up). If you must flash, download from trusted sources and verify the checksum. For most users, consider replacing the device instead – the A4s is low-spec and firmware support is virtually nonexistent. Note: Do not uninstall com