One week ago, it was reported that the latest flagship killer, i.e. OnePlus 5, is suffering from a severe affliction. Some users have discovered it at the least convenient time. It turned out that this smartphone may reboot when dialling emergency number, i.e. 911 in the United States or 112 in Europe. Unfortunately people discovered this error when they needed to call for help.

The discovery was publicized by one of the users of the world’s largest online community, the Reddit forum. He tried to call for help with the 911 number when he saw a burning house in Seattle. To make matters worse, the situation with restarting OnePlus 5 occurred twice during the whole accident. Later in the house, he was able to reproduce the issue and capture it on video recording. OnePlus has decided to contact his client as soon as possible to investigate the root cause of this problem. Two days later, the fix was available.

OnePlus published an official statement on the cause of the problem.

The source of the problem was an incorrect memory allocation by the communication chipset:

The source of this issue was related to a modem memory usage issue that triggered reboot. This reboot was a random occurrence for some users on VoLTE network where OTDOA protocol was triggered when placing an emergency call.

The OTDOA (Observed Time Difference Of Arrival) technique is used to accurately determine the user’s location during the call to emergency number. Thanks to precise measurement of signal propagation time from 3 LTE base stations to user, OTDOA protocol allows determining location even when the smartphone does not receive GPS signal.

To solve the problem, OnePlus worked with the chipset manufacturer, Qualcomm. The fix was included in the OxygenOS 4.5.6 update.

Source: OnePlus