YBKJ A20 JN

= Identification =

The device is completely generic, there are no labels of any kind and it comes in a plain brown cardboard box, obviously without any manual. The only markings on the black plastic case are the green Android Robot logo and "Smart Media Player" written in small characters.

The PCB has the following silkscreened on it: YBKJ_A20_JN_V2.2

In android, under Settings->About Tablet, you will find:
 * Model Number: SoftwinerEvb
 * Build Number: sugar_ref001-eng 4.2.2 JDQ39 20140403 test-keys

= Sunxi support =

Current status
I have added this device to my local git copy of u-boot (it requires a slightly different configuration from other A20 devices) and should upload the patch as soon as I have sufficiently tested it, which should take a couple more days.

As for the kernel, I am testing the present sunxi 3.4.xx master branch.

Manual build
Everything else is the same as the manual build howto.
 * For building u-boot, use the YBKJ_A20_JN target.
 * The .fex file can be found in sunxi-boards as ybkj_a20_jn.fex

= Tips, Tricks, Caveats =


 * 1) It seems this board is quite picky with the brand/type of SD card it will accept. The only one I have working now is a Samsung Class 10 16GB microSD card with an original Samsung microSD to SD adapter.
 * 2) This board includes a USB hub chip (GL850) which provides the two USB HOST ports on the side next to the SD card slot.
 * 3) There is no AXP209 Power Controller!

FEL mode
The USB OTG port is the USB port on the back.

Between the DC power connector and the SPDIF, there is a pinhole. Behind this is the button which triggers FEL mode.



= Adding a serial port =

Device disassembly
There are no screws holding the two halves of the case together. The bottom half has a big clip in each corner, and small clips in the middle of all sides except the back. Carefully insert a plastic tool / blade / thin screwdriver between the two halves, and gently push the clips to the inside until you release them. Start with one corner and progressively work your way around the case edge.

Be careful when opening the device, as the cable to the WiFi antenna (glued to the top cover) is quite short.

Locating the UART
While there are 3 UART connectors on the board, the one between the WiFi module and the RAM chip is UART0 which can be used for u-boot and kernel debugging. It is clearly labeled, just solder on some wires according to the UART howto.

= Pictures =

= Also known as =

= See also =
 * YBKJ A20: Another A20 HTPC, different form factor, components and PCB, but apparently from the same PCB designer ("YBKJ").
 * TXCZ A20: Same form factor HTPC, different PCB and components.
 * Langcent h6s: Same form factor HTPC, different PCB and components.