DM8168 Z3 BOOTP recovery procedure

 Host side preliminary work

There are two BOOTP servers available for GNU / Linux. One of them is CMU bootpd and the second one is actually a DHCP server, ISC dhcpd. In Debian GNU / Linux these are contained in the bootp and isc-dhcp-server packages respectively.

• We will be using ISC dhcpd which is quite easy to get up and running since it treats BOOTP clients as a kind of special case of DHCP clients. To install the package, simply run the following line on your host computer (the one that is going to serve as the BOOTP server).

sudo apt-get install isc-dhcp-server

• Once isc-dhcp-server has been installed, the server's configuration file will be added under /etc/dhcp/dhcpd.conf. Please find below a reference dhcpd.conf file that has been successfully during the BOOTP recovery of a bricked Z3 EVM board. These lines can be added at the bottom of the configuration file.

The parameters in this configuration file that need to be set are the following:

- subnet and IP addresses range: Represents the range of valid IP addresses that will be given to the devices connected to the private network (remember that BOOTP is a special basic case of DHCP).

- filename: The path to the u-boot binary image.

- hadware ethernet: MAC address of the board that needs to be recovered.

- fixed-address: The address that will be assigned to the board through the process.

IMPORTANT: A fixed IP address should be assigned to the BOOTP server machine (desktop machine in our case) so that it belongs to the same private network specified in the configuration file.

option subnet-mask 255.255.255.0;
default-lease-time 600;
max-lease-time 7200;
subnet 192.168.0.0 netmask 255.255.255.0 {
range 192.168.0.20 192.168.0.100;
}
host clientname {
filename "/srv/tftp/u-boot.bin.img";
server-name "server";
next-server server;


#Z3 EVM
# hardware ethernet 64:7b:d4:62:e2:22;
# fixed-address 192.168.0.30;


#Customer's board
hardware ethernet 50:56:63:47:6d:c8;
fixed-address 192.168.0.40;


allow bootp;
}

• Restart dhcpd by issuing the /etc/init.d/isc-dhcp-server restart command.

• Make sure that the following images / scripts "u-boot-uartboot.bin.scr, u-boot-uartboot.bin, u-boot.bin and u-boot.bin.img" are copied into the BOOTP server (In this case we used the regular TFTP server path used by the SDK under /srv/tftp). These images can be found among the pre-built images available inside Z3's z3-netra-RPS-xxxx tarball (as a customer, access should have been granted by Z3 to their downloads directory).

Reconfigure jumpers on 1-2, 3-4 and 5-6 of jumper block J20 (holding the Z3 module card so that the LED and power switch are at the top right, the leftmost jumper is 1-2)  The factory default is 5-6, 9-10 and 15-16.

Power up the system. While in BOOTP mode, the module retrieves its IPL code from the BOOTP server; the IPL code runs and retrieves the remaining software components from the TFTP server.

Open the serial console, at this point, a valid u-boot prompt should already be available.

Proceed to issue a "make installbootloader" from the root of the devdir (The firmware deployment method selected should be "Attached board on communication port").