You might be trying to install an OTA update only to get Unzip Error just as you are about to restart and install the update.zip. The problem is that your OTA update app is getting hibernated during the download, causing the file to get corrupted. This points at a RAM management bug on your current firmware which causes minimized apps to stop working or malfunction.
A fix I've found is to avoid minimizing the OTA update screen during the process. This means you must keep it active and not open any other apps till the download is complete. You could also set the screen timeout to 30 minutes to keep the screen active.
Alternatively for those who have steady power source, navigate to Settings > Developer Options > tick "Stay Awake" , then connect your device to a charging source. This would keep the device awake so long as its charging. (You can turn it off once you are done with the update)
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