A20 Board doesn't boot

[lorenzownd]

Hi. I received my A20-OLinuxino-Micro (no nand) a few days ago and I have some troubles getting it working. When I power it on using either USB-OTG, battery or power supply (unfortunately I have only a 5V 2A power supply) I get no signal from my native HDMI monitor. I'm using the official Debian image on a Class 10 8GB uSD card. The only response I'm getting from my board are the 2 leds of the ethernet port. I tried using

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nmap -sP 192.168.1.* but the board doesn't show up, even if I edited /etc/network/interfaces to make the board automatically connect to internet. One thing I noticed is that when I scan for connected hosts with nmap the board's ethernet led starts blinking very fast for a short time (so I guess the board is reacting in some way). I also tried to connect some USB devices to the board, but I get no response from them (e.g. mouse laser, keyboard leds). At this point I think the board is not booting at all! The big problem is that I have no USB UART cable (for now) to debug the boot process. Do you have any ideas on how to get it working?

[Lurch]

The A20 board won't work with OTG-USB power alone. You really need 12V@1+ A to reliably work with the board.
If it partially booted and then was turned off, the sdcard image might be corrupted - in which case you will need to reflash it. Without the USB Usart cable it's tough to see what's going on.

[lorenzownd]

Thanks for the quick reply. Do you think my board may not be booting correctly because of the "bad power"? Unfortunately at home I have only a 5V 2A power supply and a 12V 3.4A one. I didn't connect the second power supply because I thought that 40W+ were too much for this little board. Soon I'll get that USB UART cable/converter, but I posted here because I thought that the board with the original image should work correctly.

[BMK]

Don't worry about the amp rating as long as its > 1A, you are sure it's DC  and you have the polarity right it will be fine

[lorenzownd]

I changed the power supply, but still no luck.

[BMK]

Debugging this without the UART cable is a pain. Having said that, if it is a new board there is pretty much nothing that can prevent it from booting except an incorrectly made SD card or wrong power supply. *(unless you fried something already...)


Does Red LED beside Li-Po connector come on when you apply 12 Power?
Does the Green LED ever light?

The green LED should light solid whilst booting up, then changes to blinking once the boot is complete.

How did you write the SD card? 

[lorenzownd]

The red light turns on when I apply the power supply, but I haven't seen any green led turned on since I had it. Does that mean it's simply not booting or it may even mean it's an hardware issue? I used only the power supplies mentioned above (5V 2A, 12V 3.4A, USB-OTG and 4400mAh Olimex battery) and I haven't noticed any strange things like smoke or sparks. I hope my board is not already broken
BTW I wrote the original debian image using Win32DiskManager, as said in the wiki.

[BMK]

If you have no LED, that means the board isn't booting. I'd say most likely this means something wrong with the SD card. Did you try to re-flash it?. Don't adjust anything (e.g network settings) on the card after you flash it. The network settings are easy to solve once you get the board booted.

On Mine, the green LED won't light unless there is a bootable SD inserted.

I would try to re-flash the card

Another thing to notice is that even with the network cable disconnected you should see both LEDs on the Ethernet PHY light up for a brief time after you apply power.

[lorenzownd]

Thanks a lot, I was just thinking it was an hardware fail! I tried to reflash the image many times, but I may be doing something wrong. So let's start from the very beginning. Here is what I do, step by step:
- Unpack the archive containing the image
- Insert my uSD in my computer (through usb adapter)
- Start Win32DiskManager
- Select the image
- Write the image
- Insert the uSD in the board

Note that I don't delete all the card's partitions before rewriting the image, do I have to do it?

[BMK]

That should be all you need to do.

Warning the remainder of this post will sound patronising to you if you already know these things

You downloaded the wrong image?? There are lots of images for different OS and boards in the wiki.

Re-download the image anyways in case something got corrupted

There was an error either in the decompression or the download of the image?? I don't think win32diskimager cares and will just blindly duplicate the image to the card.

I usually format and remove partitions before writing the image, although I believe w32diskimager does this anyway.

In the past I have accidentally written the image to a card or a USB flash drive by mistake. Make sure you have the correct drive selected. Diskimager defaults to the first flash drive or card it can find. Maybe it has chosen the wrong disk/card.

On a windows machine, the correctly written image will only show as a 16MB raw partition (look in disk management).  It will only show up as one removable drive. You should not be able to see any files or folders in it. Clicking on it in explorer should lead to windows error message or an invitation to format-this is what you want.

The best way to inspect the written card is to mount it on another linux machine. If you don't have one, then you are best to get a VM. This one I used recently.

http://www.thoughtpolice.co.uk/vmware/#debian7.0

[lorenzownd]

Now I'm not at home, so I can't make any test.
- I downloaded the image here http://olimex.wordpress.com/2014/03/07/building-a20-olinuxino-micro-debian-image-with-hardware-accelerated-video/
- I downloaded 3 times the image
- I have Xubuntu 13.10 and Windows 7 (64 bit)
- I remember that the 16 MB partition should be vfat filesystem, so why Windows shouldn't read that? In fact, after writing the img to the uSD I can clearly see the 16 MB partition and the files in it under windows; but if you're sure windows should not read it correctly, that would mean that my fs is wrong. Do you think the program (Win32Image...) may be using a normal fat32 fs instead of vfat?

EDIT: I used blkid tool under Xubuntu and it actually reports /dev/sdb1 (16 MB partition) is VFAT while /dev/sdb2 (4 GB partition, the remaining 4 GB are unpartitioned) is EXT3

[lorenzownd]

Debugging this without the UART cable is a pain

I purchased a USB UART device a few days ago to debug the board

[lorenzownd]

Finally after 1 week I received my USB-UART interface. After having set up everything, I get this error just after powering the board  :

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U-Boot SPL 2013.10-rc2-08400-g8a4621c (Oct 29 2013 - 15:24:26)
Board: A20-OLinuXino_MICRO
DRAM: ? ? 0 MiB
### ERROR ### Please RESET the board ###


Don't need to say that I tried to reset the board many times.
From what I can understand, I think it's a faulty RAM module. What do you think?

P.S. I used PuTTY for Windows with a baud rate of 115200

[JohnS]

Write a new SD card (with correct uboot etc) and see what that does.  You may have a corrupt uboot now.

Also check your power supply as cheap ones give troubles like you see.

John

[lorenzownd]

I wrote the official Debian image on my uSD another time but still no success, it gives me the same error. I will also try to get another power supply, but I don't think it's the problem because the current one didn't give me any problems so far with other things.