How can I determine if the board is working?

[charlieholimex]

I have the A20 with on board NAND flash.

I inserted Debian image micro SD card I got from Olimex, plugged monitor into hdmi, and applied power through micro usb. First time it booted Android. Then I reset, and it booted Linux. Then I powered off, and now it won't do anything. When I apply power, a green LED turns on for a few seconds. Nothing on the monitor.

There is some activity on Ethernet lights, but whatever the board is booting, if anything, it is not attempting to obtain an IP address over DHCP.

How do I know if the board is even working under these circumstances?

[Lurch]

If the green LED goes off after a few seconds, it's dead.  Possibly an error on the sdcard?
Powering through the OTG port is flakey at best - you should really be using the barrel connector with 12V.

You really need a UART-2-USB converter connected to UART0 on the board to see the boot log while it is booting.
maybe this: https://www.olimex.com/Products/Components/Cables/USB-Serial-Cable/USB-Serial-Cable-F/
The brand isn't important.

In the mean time, I would try powering with 12V on the barrel connector and another SDCard to see if that is the problem.

[charlieholimex]

I downloaded the latest Linux image to the SD card, and it's booting Linux again now. Also using barrel power. Thanks.

[charlieholimex]

OK I think I see what's happening.

The board won't boot if there is an ethernet cable plugged in.

If I unplug the Ethernet cable, then boot, then plug in Ethernet, then dhclient eth0, I get an address on my lan.

I can ping yahoo.com successfully.

But if I launch iceweasel, the A20 crashes.

And I can't boot with the Ethernet cable plugged in.

I've tried two different cables. DHCP and ping work. It's an ordinary  managed switch with six other computers running through it.

a20_debian_kernel_3_4_LAN_USBx2_Cards_LCD_HDMI_SATA_TS_X_GPIO_OTG_MIC_release5.7z

[charlieholimex]

I knew the answer right after I clicked "Post". Insufficient power.

I increased to 12V/1 Amp and all is well now.

[Lurch]

Yeah, I should have mentioned the 1+ Amp thing. Sorry.
At least your weekend is saved ... have fun.

[rzr]

Edit: I have finally copied the uboot on sdcard and it's booting fine ...


Orig:

May this help but a20_debian_kernel_3_4_LAN_USBx2_Cards_LCD_HDMI_SATA_TS_X_GPIO_OTG_MIC_release5.7z
could not fit into my 4GB sdcard , I had to mount an copyfiles ...

It would help to shrink the part before publishing it and expand it once rebooted (like rpi-config)