Device is not updated after update

[biothunder]

Sometimes, i found that my firmware still at the old version after update complete, there is no any error.It same happen on use Android-nRF-Toolbox to update firmware.

code:

implementation 'no.nordicsemi.android:dfu:1.9.0'

   val starter = DfuServiceInitiator(dfuDevice.address)
            .setDeviceName(dfuDevice.name)
            .setKeepBond(false)
            .setPacketsReceiptNotificationsEnabled(true)
            .setPacketsReceiptNotificationsValue(1)
            .setUnsafeExperimentalButtonlessServiceInSecureDfuEnabled(true)
    starter.setZip(savePath)
    starter.start(context, DfuService::class.java)

test phone: Redmi Note 4X Android 7.0