An investigation into devices that are able to hide data by using a factory reset option discovered that the option did little to delete potentially sensitive information.
The three separate investigations of Android's data deleting systems found it was actually possible to recover information. In some cases, a reset just removed the list of where data was stored and deleted nothing else.
Tesco's Hudl tablet was found to have a major flaw that allowed hackers to get at data saved to onboard memory.
According to security expert Ken Munro at Pen Test Partners, who worked with the BBC to test second hand models of the device, The Hudl was considered vulnerable because of a known bug in the Rockchip processor at its heart and a flaw in the firmware, this allowed an attacker to read from it as well as write.
In response, a Tesco spokesperson said: "Customers should always ensure all personal information is removed prior to giving away or selling any mobile device. To guarantee this, customers should use a data wipe program."
The spokesperson also added that any tablets that were returned to Tesco would have all personal data wiped before they were re-sold.
