Flashing Cisco 7912G
About 10 Cisco 7912G IP phones that were killed came to me not so long ago. When turned on, the
hold lamps and the menu were on at the same time, the display was empty. Googled that with such a phone
is dead and it needs to be reflashed with a programmer. Because I really did not want this, I began to look for
workarounds. I started a dhcp server on my laptop, the phone began to receive an IP address, which means it’s
more or less alive, only the firmware has flown.
I began to look for documentation on the firmware - there is practically nothing, I can’t
find the firmware , on the cisco website they offered to conclude a support agreement in order to gain access to the
firmware. I had to collect information bit by bit.
We
install the necessary software: apt-get install tftp tftpd dhcp3-server
In Cisco ip phones, if there is no firmware or if it is damaged, the phone takes the ip
address from the dhcp server and tries to pick up the firmware from the tftp server specified in dhcp.
dhcpd.conf: We start the dhcp server, look in the syslog command: tail -f / var / log / syslog (we need root rights) We see that the phone is trying to take the cp7912r.zup file from the TFTP server. I could not find this file. I downloaded the firmware for sip from the pirate bay , inside the archive there is a file CP7912080001SIP060412A.sbin, which must be renamed to cp7912r.zup and put in / srv / tftp /
Crosspost from my blog
hold lamps and the menu were on at the same time, the display was empty. Googled that with such a phone
is dead and it needs to be reflashed with a programmer. Because I really did not want this, I began to look for
workarounds. I started a dhcp server on my laptop, the phone began to receive an IP address, which means it’s
more or less alive, only the firmware has flown.
I began to look for documentation on the firmware - there is practically nothing, I can’t
find the firmware , on the cisco website they offered to conclude a support agreement in order to gain access to the
firmware. I had to collect information bit by bit.
We
install the necessary software: apt-get install tftp tftpd dhcp3-server
In Cisco ip phones, if there is no firmware or if it is damaged, the phone takes the ip
address from the dhcp server and tries to pick up the firmware from the tftp server specified in dhcp.
dhcpd.conf: We start the dhcp server, look in the syslog command: tail -f / var / log / syslog (we need root rights) We see that the phone is trying to take the cp7912r.zup file from the TFTP server. I could not find this file. I downloaded the firmware for sip from the pirate bay , inside the archive there is a file CP7912080001SIP060412A.sbin, which must be renamed to cp7912r.zup and put in / srv / tftp /
ddns-update-style interim;
ignore client-updates;
# Опция с указание tftp серверов для телефона Cisco 7912G, у других моделей
# код отличается.
option option-150 code 150 = ip-address;
option option-150 192.168.5.1;
default-lease-time 21600;
max-lease-time 43200;
# Подсеть на интерфейсе ноутбука
subnet 192.168.5.0 netmask 255.255.255.0 {
option subnet-mask 255.255.255.0;
option broadcast-address 192.168.5.255;
option time-offset -18000; #
option option-150 192.168.5.1;
# TFTP сервер (в моём случае ноутбук, к которому подключался телефон)
next-server 192.168.5.1
# Подсеть адресов, с загрузкой по tftp
range dynamic-bootp 192.168.5.2 192.168.5.100;
}Crosspost from my blog
