According to foreign media reports, users reported that Lumia 1020 and 925 encountered crash bugs when upgrading to WP8.1 preview or subsequent versions. The specific bug phenomenon is that the device cannot wake up after locking the screen, and it needs to be restarted to recover, and the probability is high. At present, Microsoft has made it clear that the bug is known to the table, and will provide updates and fixes in the near future.

Kevin Lee, partner director of Microsoft's project management department, said in the announcement:

I’m sorry we’ve been dark – I work closely with the Lumia engineering team that’s working directly on this. Trying to shed a little light on this…

Beginning in early September we started to receive an increased number of customer feedback regarding Microsoft Lumia 1020 and 925 device freezes. During the last two months we have been reaching out for more and more data and devices to systematically reproduce and narrow down the root cause. It turned out to be a power regulator logic failure wh ere in combination with multiple reasons the device fails to power up the CPU and peripherals after idling into a deep sleep state.

I am pleased to pass on that we have a fix candidate under validation which we expect to push out the soon with the next SW update!

Appreciate your patience.

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