It is now possible to load firmware binary files from removable media when they're provided externally to Debian installation media.

The installation media are now provided with an application that allows preparing the system to install Debian from Microsoft Windows environments.

When used with functional network access, the installer will upgrade all packages that have been updated since the initial release of lenny. This upgrade happens during the installation step, before the installed system is booted.

As a consequence, the installed system is less likely to be vulnerable to security issues that were discovered and fixed between the release time of lenny and the installation time.

The installer can now optionally set up the installed system to use updated packages from volatile.debian.org. This archive hosts packages providing data that needs to be regularly updated over time, such as timezones definitions, anti-virus signature files, etc.

An interactive boot menu was added to make the choice of specific options and boot methods more intuitive for users.

The armel architecture is now supported. Images for i386 Xen guests are also provided.

Several devices designed to provide hardware speech synthesis are now supported by the installer, therefore improving its accessibility for visually-impaired users.

The installer can now set up partitions with the relatime mount option, so that access time on files and directories is updated only if the previous access time was earlier than the current modify or change time.

The computer clock is now synchronized with NTP servers over the network during installation so that the installed system immediately has an accurate clock.

Thanks to the huge efforts of translators, Debian can now be installed in 63 languages (50 using the text-based installation user interface and 13 supported only with the graphical user interface). This is five languages more than in etch. Languages added in this release include Amharic, Marathi, Irish, Northern Sami, and Serbian. Due to lack of translation updates, one language has been dropped in this release: Estonian. Another language that was disabled in etch has been reactivated: Welsh.

The languages that can only be selected using the graphical installer as their character sets cannot be presented in a non-graphical environment are: Amharic, Bengali, Dzongkha, Gujarati, Hindi, Georgian, Khmer, Malayalam, Marathi, Nepali, Punjabi, Tamil, and Thai.

The country choice list is now grouped by continents, allowing an easier selection of country, when users don't want to pick the ones associated with the chosen language.