Google has addressed a security concern with the Face Unlock system on its Pixel 4 smartphones, more than five months after the devices went on sale.
In October 2019, a BBC News test found the Face Unlock system allowed access to a person's device even if they had their eyes closed.
Security researchers criticised the feature, as it could allow unauthorised access to a smartphone.
Google updated the Pixel software on 6 April to address the issue.
But the fix was not enabled by default on two Pixel phones tested by BBC News.
Apple added Face ID to the iPhone in 2017 - but it has always had a setting labelled "require attention for Face ID".
The setting is on by default and checks the user's eyes are open and looking directly at the iPhone before unlocking.
Images of the Pixel 4 leaked before it was officially revealed showed a similar setting in its facial-recognition menu.
But when the smartphone went on sale, on 24 October, it was without the feature .
The company told BBC News it would improve Face Unlock over time.
Even after the fix, Google's Face Unlock system only checks that the user's eyes are open.
Apple's Face ID system checks the user is actually looking at the iPhone.