In an earlier post, I have explained how "clockworkmod" has been installed on my HTC Wildfire (Buzz) phone. This is a "recovery" mode that permits one to install the "superuser" application, that gives root access to the phone. One can then use this to install Debian. One can also use "clockworkmod" to install the Cyanogen version of the Phone OS Android (as developed by the Android Open Source Project).
The "superuser" application Superuser-3.1.3-arm-signed.zip can be downloaded from "andoidsu.com". It can then be put on the SD card. Since one does not have "root" access, this cannot be installed---and that appears to be a "Catch-22". However, by booting into ClockworkMod "recovery", one can select this application to be installed as an "update" to the existing operating system. This then installs the relevant binary "su" so that one can log in as root after booting the phone.
In addition, this installs a "superuser.apk" as a system application so as to control if and when an application running on the phone is granted "root" privileges. In case, non-market applications are disabled on your phone (as they usually are on mine) then you must temprarily enable such applications in order to complete the installation of "superuser.apk".
Having done this one can follow the excellent guide or an alternative guide to install and use Debian in a chroot. I join the authors of those write-ups in thanking the developers who made it possible to use my phone this way!
Finally, if one is tired of pussy-footing around with the existing operating system, it is best to download the latest stable build of Cyanogen for Buzz by following the instructions regarding Buzz on the Cyanogen Wiki. However, the instructions page indicates that gaining "S-OFF" is necessary. It is not!
The downloaded ".zip" file needs to be placed on the SD card. We then reboot the phone into ClockworkMod recovery. It is best to take a backup before doing anything else. The backup will be stored on SD card. Next one uses the "recovery" menu to wife the the main partition, the "userdata" and the (Dalvik) "cache". After this one selects "install from .zip" file in the ClockworkMod recovery menu. Finally, once installation is complete, one can boot into Cyanogen.
Note that the first boot takes a while. Be patient, have a snooze or something! The great thing one notices after the installation and first-boot is complete, is how responsive the phone has become! Moreover, the memory and storage usage has also been drastically reduced. Now all one has to do is to restore the Concats (which were stored as vcard on the SD card) and one is good to go!