Posts Tagged ‘Utils’

Creating Bootable Cisco ISO Images

Wednesday, December 26th, 2012

Thanks to this writeup for a cool method of getting Cisco full install bootable ISOs from non-bootable updates. I’ve used this many a time to get servers up in my LAB when I haven’t had access to bootable ISOs yet. Below are the boot files extracted from various bootable versions of CUCM disks. It seems that only 2-4 bytes at 0xC are different. The rest of the file is identical between versions.  While putting all of this together, the hacker in me wanted to dive into what those specific bytes refer to so I got distracted for about 4 hrs while I read the ISO 9660 and El Torito specs. (No, I didn’t get far enough to figure it out… maybe another time when the ADD kicks in again. But anyway…) Here are some the bootfiles for disks I had laying around.

**This would  not be supported by TAC. Use only in LAB environments.

UPDATE 12/28/2012:

I played around a little more with this today. The bootfile extracted by UltraISO in the steps above is actually part of syslinux (specifically isolinux). This is the standard tool used to make a Linux bootable cd/dvds. The extracted file above is simply the isolinux.bin file that is used by isolinux when creating a bootable disk (inserted at sector 17). It follows the El Torito specs (part of iso9660) that isolinux uses for a non-emulated boot of a cd/dvd.

Here’s the cool thing… every Cisco ISO has a copy of the bootfile that was used to generate the El Torito boot image for the bootable version of the disk … Simply mount the non bootable ISO, grab the isolinux/isolinux.bin file and then continue to use the steps for UltraISO to add the file to make the image bootable.


This way you don’t even need to find a working bootable ISO to steal the bootfile from or someone to post bootfiles from different versions. I went through 4 different major CUCM iso releases and compared the extracted bootfile with the isolinux/isolinux.bin file. Minus some padding at the end of the file, isolinux.bin on the disk is identical to the extracted bootfile from a bootable version.

On a side note… I’m working on a perl script to do everything UltraISO does but in mac. I hate being dependent on windows apps.

Further Reading:


Getting Started with GeekTool on OSX

Thursday, December 13th, 2012

Just started playing around with GeekTool yesterday. I love this little app. It’s got so many possibilities. Anything that lets me tweak my interface and involves the cmd line I go nuts over. After looking through a few examples, I decided to write a little script that would display my local NIC IP addresses on the desktop. I figured it was a good project to familiarize myself with the way it worked.


MAC mini ESXi Custer

Sunday, February 26th, 2012

So like most geeks in IT, I have a home lab. The problem with mine is… it is loud… and it is HOT… Recently I purchased a mac mini, popped 16GB in it, and attempted to use this to get a quiet, low power, low heat esxi host. Unfortunately the default boot image of esxi did NOT recognize the integrated gige nic.  A little research led me across a program called the esxi customizer. This allows you to modify the esxi iso that you download from vmware to include other drivers. And boom…

Since this was such a success, I’ll  slowly be switching out all my other rack mounts for mini’s. I”ll take a little performance hit (maybe, older cores were core 2 and gen 1 i7′s, this is all sandybridge), and drop the segmented storage network, but with the power, heat and noise savings, it is worth it. I already have compact SANs in the form of a QNAP SS-839 Pro and TS-439 Pro that I use to iscsi attach the esxi hosts so I can play with DRS/FT/Vmotion/Storage Vmotion. What I’ll end up with  is a 3-4 node esxi cluster with 2 iscsi SANs that is quiet, fast, cool, and about 6U in height for less than ~$3,500

Also of note, I was using my thunderbolt attached monitor to set this guy up and saw that esxi recognized the thunderbolt gige nic as well. This makes me think that when Apple releases the thunderbolt gige adapter in September, I should have no problems adding an additional NIC(s) and regain my dedicated storage network for esxi.

If anyone wants a shortcut to creating all this yourselves, I have posted the ISO I used along with a util that can copy this to a thumb drive so that you can USB install esxi.

Also many thanks to this post for making this all possible:

Enabling Trim For Non-Apple SSD’s in OSX Lion

Thursday, December 22nd, 2011

Great article on getting trim to work in Lion. Just added a new SSD to my MBP wanted to take advantage of trim support on the drive.


Add Cisco Web Searches to Your Browser

Monday, September 22nd, 2008

Want to easily search Cisco or it’s subsites such as the Bug ID or command lookup tool without going to Then simply add Cisco search to your browser search bar. Works in IE and Firefox on both Mac and PC. Find out the details here.