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Frequently Asked Questions about Das U-Boot

This is a collection of some of the most frequently asked questions about running Das U-Boot on the Blackfin processor.

U-Boot takes forever to write to flash!

There was a bug in the flash driver in older versions of U-Boot (and thus the version found on many development shipped boards) that caused flash operations to take an inordinate amount of time, even with quite small files. If you install the latest release of U-Boot, the amount of time required to write to flash should return to normal.

Flash on BF533-EZKIT does not work

Please check the bf533-ezkit page which explains this.

ERROR: 'ethaddr' not set

In order to communicate on the network, U-Boot needs to know the board's MAC address. This is normally accomplished by reading the ethaddr environment variable. If this is not set in the environment, then it will need to be set specially according to the board you're running. This is typically accomplished by setting aside a small sector in the flash and storing the MAC address in there. If the flash is erased and thus the MAC value reset, you can easily hit this error.

For details about the BF537 STAMP board, please see this page.

Unable to TFTP files

After you've checked to make sure your ipaddr and serverip are configured correctly, check the setting_up_a_tftp_server page. If you're still experiencing troubles, doubly check to make sure your firewall is not blocking connection attempts from the board.

U-Boot does not compile

In most cases, if you cannot compile a U-Boot release, it is because the toolchain version you are using does not match the U-Boot version. For more information, see this FAQ.

I programmed U-Boot into the flash but don't see any output

Make sure your BMODE (boot mode) is set properly. On the STAMP/EZ-KIT boards, you want to set this to bypass boot-rom so that the code will be directly executed out of parallel flash. Please see the relevant board documentation pages on this wiki for information on how to change the BMODE.

Ping doesn't work

Ping from U-Boot to a host should work. Ping from a host to U-Boot should not.

U-Boot uses a polling interface for networking - if you have not run a command, it will not respond to any packets.