Laguna Recovery

The Laguna Cavium processor can get into a mode when an invalid image has been flashed to the board. This mode can be seen when the JTAG program is stuck on Core 0 DRAM 00%.

Valid images on Laguna boards will be 16MB in size and be labeled with a file extension of .bin.

A common mistake is to flash a file such as openwrt-cns3xxx-squashfs_laguna_spi.bin which is only around 9 or 10MB.

Please note on the Laguna boards, there is SPI flash and NOR flash. Please read more to find out which board you have. ​http://trac.gateworks.com/wiki/laguna/openwrt

The board is stuck where the JTAG programmer can’t release the CPU out of reset.

​http://trac.gateworks.com/attachment/wiki/lagunarecovery/linuxhang.jpg ​http://trac.gateworks.com/attachment/wiki/lagunarecovery/windows.png

Workaround

Gateworks has come up with a work around for this, however, it is very precise and extreme care must be taken to not damage the board.

You can read about the fix on below, but please do not attempt it if you do not feel comfortable.

Please prepare the JTAG program on the PC with a valid Laguna binary, acquired from our list of pre-approved binaries here: ​​http://svn.gateworks.com/laguna/images/

1. Connect JTAG Cable to board and computer
2. Ensure the board is not powered
3. Take a pair of metal conductive tweezers and short two pins together. Pin 1 is marked with a white dot. Pin 2 is next to pin 1. See below pictures for an example.
   • GW2380/GW2382 - Pins 1 and 8 of U15
   • GW2391 - Pins 4 and 5 of U3
   • GW2388 - Pins 4 and 5 of U11
   • GW2387 - Pins 4 and 5 of U5
4. Power on the board with tweezers in still held in place
5. Start the JTAG program
6. When the program gets to "Loading Debugger" Remove the tweezers
7. The program should continue as expected and not be stuck on Core 00 DRAM.

GW2380/82 Example

GW2388/87/91 Example

NOTE: The picture is an example, please see above for exact IC chip.