View Full Version : [SOLVED] alternate install with external PATA CD-ROM using Cypress Semi chipset

May 27th, 2010, 12:11 AM
Oh boy, this was a doozy. Maybe this will help someone out.

This applies to you only if you meet ALL of the following four conditions:
you're trying to install Ubuntu 10.04 alternate CD (or, heck, maybe a later version if this bug doesn't get fixed).
you've got a USB-connected external PATA CD-ROM drive
the chipset used in that external CD-ROM enclosure is a Cypress Semi
while going through the install, you get a pop-up message that says, "No common CD-ROM was detected".
Again, this only applies to people using a Cypress Semi chipset; don't waste your time with this if you're not in this boat. If you're not sure which chipset your external CD-ROM drive uses, connect it to a Linux box that works, and type 'lsusb'. But that's beyond the scope of this here post.

Here is the fix to get things working. You'll need to find a working computer that already has the version (e.g. x86, amd64, etc) of Ubuntu 10.04 installed on it which is identical to the version you are trying to install. I realize this is a bit of a chicken-and-egg problem. Good luck with that.

On a working Ubuntu 10.04 PC:
Insert a USB stick.
Copy the file called
to the USB stick. Note that your kernel version (e.g. 2.6.32-21) may be slightly different in the last 2-digit number; that shouldn't be a problem.
Now, on the PC where you're trying to install Ubuntu, when the error message pops up during install, do this:

"Load CD-ROM drivers from removable media?" --> Choose NO.
"Manually select a CD-ROM module and device?" --> Choose YES.
"Module needed for accessing the CD-ROM" --> Choose NONE (only choice).
At the next screen, hit Alt-F2. You will be dumped to the command line. Press Enter for the command prompt.
Type 'ls /dev/s*' to get a list of devices. Take a good look at this list, and maybe even write it down.
Insert the USB stick.
Type 'ls /dev/s*' again to get a list of devices. Note which device is NEW, which corresponds to the USB stick. For me, it was /dev/sdb1. In the following, I will assume it was also /dev/sdb1 for you (so replace it with whatever below if it's something different for you).
Type these commands

mkdir /media/tmp
mount -t vfat /dev/sdb1 /media/tmp
cd /media/tmp
insmod ums-cypress.ko
Wait a second or two. Hopefully the CD-ROM drive starts spinning. Type 'ls /dev/s*' again, and hopefully yet ANOTHER new device shows up. For me, it was called /dev/sr0.
Press Alt-F1. Back to pretty color land.
In the input box which probably says '/dev/cdrom' by default, change it to '/dev/sr0' or whatever is the case for you.

Hope this helped.