Frequently Asked Questions - NanosG20

The boot sequence changed some time ago. J3 is used to bypass the NAND preventing the ROM code to load at91bootstrap from that media.
Since the BCH update in March 2013 (see, we do not consider the NAND to be the proper location for at91bootstrap. That is why we switched to the DataFlash which is equipped on all Stamp9G20 and NanosG20 boards since 2013. The DataFlash however uses a different chip select that has to be bypassed to prevent autoboot.
Please see to figure out which jumper is used when the DataFlash is used. In case of doubt where at91bootstrap is stored on your board, it is perfectly okay to close both jumpers during boot.

We will try to produce products as long as possible. This means, that there will be hardware revisions and changes of the used components if necessary. Of course, the most important factor for every product is the processor itself. Please find information about how long a certain processor is planned to be produced in the PDF attached below. In case of a processor hits its EOL, we try to offer a similar product with migration support for existing customers.

SAM9 lifetime commit Mar12.pdf322.43 KB

Related error message

debian:/# apt-get update
Ign lenny/updates Release.gpg
Ign lenny/updates Release
Ign lenny/updates/main Packages/DiffIndex
Ign lenny/updates/main Packages
Ign lenny/updates/main Packages
Err lenny/updates/main Packages
  404 Not Found [IP: 80]
Ign lenny Release.gpg
Ign lenny Release
Ign lenny/main Packages/DiffIndex
Ign lenny/main Packages
Ign lenny/main Packages
Err lenny/main Packages
  404 Not Found [IP: 80]
W: Failed to fetch  404 Not Found [IP: 80]
W: Failed to fetch  404 Not Found [IP: 80]
E: Some index files failed to download, they have been ignored, or old ones used instead.


Debian support for Lenny distribution ended in 2012. There are two solutions for this problem.

First, you can select a mirror still supporting Lenny. In order to do so, exchange the content of /etc/apt/sources.list by:

deb lenny main

As alternative, you can upgrade to Debian Squeeze. In that case substitude lenny by squeeze in the original, unmodified /etc/apt/sources.list and run the following commands:

apt-get update
apt-get dist-upgrade

After creating a new SD card from the original images the system won't boot.
Following problems are common:

  • You get a kernel panic with "no init found" message.
  • Using apt-get upgrade or similar gives you error messages like this "fopen: permission denied".

Most probably you have messed up permissions of your rootfs during copying. Please follow this Howto:

The NanosG20 uses the WAKEUP/SHUTDOWN mask of the AT91SAM9G20 microcontroller. On a regular shutdown the enable pin of the power regulator is toggeled and can be switched back by WAKEUP. WAKEUP is connected to the switch on your NanosG20. On a regular shutdown, you have to press the switch to boot your Nanos. On failure the Nanos would boot without the switch. The register settings for WAKEUP/SHUTDOWN are battery backed-up. So they persist between reboots and connecting or disconnecting the power cable, when a battery is connected.
So, when your NanosG20 does not boot:

  • First make sure, that the your power adaptor is connected with X14 between the DSUB-9 connectors. If you connect via the USB-Device port X7, J9 has to be set. Please guard not connecting both connectors at a time, when J9 is set
  • Press the switch to boot your device. If you keep the switch pressed, you will end in the boot menu.
  • The WAKEUP/SHUTDOWN mimic is locked. This can happen, if you changed the battery or battery current was interrupted. Disconnect the power adaptor. Disconnect the battery, e.g. with a slip of paper. Connect the power adaptor again and remove then the slip of paper. Your Nanos should boot now.
  • If this mimic does not fit your application, you can use J5 to disable this feature altogether. For revision 2 J5 has to be closed when using NanosG20 without backup battery.