In one of the lowest spec examples of the last one, [gvl610] has got an up-to-date Linux kernel to boot on a vanilla Arduino Uno.

Support for Android 4.2 and Ubuntu 12.04 The device also has the same Arduino sockets as an Arduino Uno, including 14 GPIO, 2 PWM, 6 ADC, 1 UART, 1 SPI, and 1I2C as well as support for camera ...

It supports both Android and Ubuntu operating systems, which is a common feature among many development boards. However, what sets the pcDuino3 apart is its compatibility with the Arduino platform.