Hello! I have 2 Udoo boards with the spec of IMX6Quad UDOO-Quad DDR3 1GB-4porte USB-WIRED & WI-FI I load Ubuntu and Andriod in 2 micro-SD cards respectively. For one of the board, both OS work fine. However for the other, only the Andriod micro-SD card works; While turning to the Ubuntu card, it hanged after the initial screen flashing. By using the USB-debug mode, I got the error message while it was booting. It looks like problem with the Ubuntu OS: [ 3.795269] Unable to handle kernel NULL pointer dereference at virtual addre ss 00000000 [ 3.803402] pgd = bf9f8000 [ 3.803414]  *pgd=4a1e5831, *pte=00000000, *ppte=00000000 [ 3.803446] Internal error: Oops: 17 [#3] PREEMPT SMP Both mini-SD cards should be no problem since both are properly working in one of the boards. Have no idea what is wrong (About drivers or hardware?). Thank for any helpful advice.