My previous tutorial is still available here but this one is a lot easier thanks to the new features introduced in Serva 2.1.

Prerequisites:

• Router: you can connect your computers directly if you have an Ethernet crossover cable, but you have to configure your server differently.
  
• Computer with Windows installed: you can use any computer-OS combination as a PXE Server as long as it has a TFTP software (even your smartphone can be a server ). In this tutorial I’m going to use  a Windows 7  PC with Serva because I think this configuration would suit the S205 owners the best. There is an alternative TFTP software for Windows called TFTPD which is more popular than Serva but in my opinion also harder to set up.
  
• Ubuntu CD/DVD: download the latest desktop version of Ubuntu from the official website.
  

(!) You should temporarily disable your firewall to avoid potential conflicts.

Steps:

1. Download and extract Serva to a folder (e.g. C:\Serva_Non-Supporter_64_v2.1.0). Choose the appropriate Serva version based on the Ubuntu edition you are about to install (x64 – 64 bit,  x86 – 32 bit). I recommend installing the  x64 edition of Ubuntu, see a comparison here) . Use the selected architecture consistently throughout this tutorial.
2. Create a root folder for Serva (e.g. C:\SERVA_ROOT).
3. Run Serva and click on the Settings button at the bottom.
4. On TFTP tab tick TFTP server and select the TFTP Server root directory you have created in the previous step (in my case C:\SERVA_ROOT).
5. Click on the DHCP tab, set proxyDHCP and make sure that the BINL box is checked.
6. Save your settings and restart Serva.
7. In your root directory you should see some files that Serva has created. Right click on the NWA_PXE folder and select properties. On the Sharing tab select Advanced sharing. Tick Share folder and set the Share name to NWA_PXE_SHARE.
8. Create a subfolder under NWA_PXE. You can name it freely (e.g. UBUNTU_12_10_X64_LIVE). Copy the contents of the downloaded Ubuntu iso into this folder and create a ServaAsset.inf file (you can use Notepad) with the following content:
   

   ;-Serva v2.1 Non-Windows Asset Information File
   ;-Boot/Install:
   ;  Ubuntu 12.10 Live
   ;-Tested on:
   ;  ubuntu-12.10-desktop-i386.iso
   ;-Require:
   ;  \NWA_PXE\ offered as MS share NWA_PXE_SHARE user=serva password=avres
   ;-Notes:
   ;  When installed on a real PC there are not passwords asked
   ;  When installed on VMWare a password is first asked (text mode); just hit enter
   ;  The GUI asks for user=ubuntu with empty password.
   [PXESERVA_MENU_ENTRY]
   asset    = Ubuntu 12.10 Live
   platform = x64
   kernel   = NWA_PXE/$HEAD_DIR$/casper/vmlinuz
   append   = showmounts toram root=/dev/cifs initrd=NWA_PXE/$HEAD_DIR$/casper/initrd.lz boot=casper netboot=cifs nfsroot=//$IP_BSRV$/NWA_PXE_SHARE/$HEAD_DIR$ NFSOPTS=-ouser=YOUR USER NAME,pass=YOUR PASSWORD,ro ip=dhcp ro

   The non-static fields are asset (you can name it freely), platform (x86/x64), user and pass (your Windows account is needed to access the shared folder) and the intitial ram disk file (Ubuntu 12.10 – initrd.lz, Ubuntu 12.04 – INITRD_N02.GZ which you have to download into the appropriate folder). Your file should look similar to this:

9. Restart Serva for the last time.
10. Start your s205 and press Fn+F11 to enter the Boot Menu. Select the PCI LAN: Realtek PXE option. If your settings are correct, after a few seconds you should see Serva’s Install Menu with the Ubuntu option. Press Enter to continue. Ubuntu will be loaded into the memory (it takes a few minutes).
11. Ubuntu Live will start with the nice Unity look and a dedicated Ubuntu installer icon. That’s it. If you want to use both Windows and Ubuntu on your S205 make sure you’ve read my tutorial on Dual-Booting before you proceed with the installation.

Source: vercot