How to extract the contents of initrd or initrd.img file?

If you have an initrd.img file use the below command to get the initrd file.

gunzip < <your_initrd.img>

You can mount the initrd file using the command:

mount -ro loop <your_initrd_file> <target_dir>

How to debug a child process using GDB?

show follow-fork-mode will give you which process you will follow after a fork by default. You can set this to parent/child using:
set follow-fork-mode <child/parent>

show detach-on-fork will tell you if we detach to one of the process after a fork. You can set this to on/off using:
set detach-on-fork <on/off>

Firefox - Error code: sec_error_reused_issuer_and_serial

Most likely it is due to a conflict in self signed certificate that you added as exception in Firefox.

Close Firefox & delete C:\Documents and Settings\<userAccount>\Application Data\Mozilla\Firefox\Profiles\<userProfile>\cert8.db. This will basically remove all the exceptions that you have added earlier.

Note: At times I had to delete the cert_override.txt file too from the same folder to get things working.

Open Firefox again, you should be good.