Update KFSN4-DRE board info

I have pointed out the various version of this board
("standard", 2S, iKVM, iKVM/IST, SAS, SAS/iKVM and SAS/iKVM/IST),
and specified their differences and which CPUs they do support,
also providing a link to the official ASUS website and to the board manual.

Also I've tested the board with the text mode ROM and it's not usable
(because it's jittery), so I'm suggesting to flash with the vesafb ROM.

1 files changed, 41 insertions, 10 deletions

diff --git a/docs/hardware/kfsn4-dre.md b/docs/hardware/kfsn4-dre.md
index e3974921..02b4dbcb 100644
--- a/docs/hardware/kfsn4-dre.md
+++ b/docs/hardware/kfsn4-dre.md
@@ -42,10 +42,35 @@ DDR2 533/667 Registered ECC. 16 slots. Total capacity up to 64GiB.
 Hex-core CPUs {#hexcore}
 =============
 
-PCB revision 1.05G is the best version of this board (the revision
-number will be printed on the board), because it can use dual hex-core
-CPUs (Opteron 2400/8400 series). Other revisions are believed to only
-support dual quad-core CPUs.
+PCB revision 1.05G is the latest version of this board and the best one
+(the revision number is be printed on the board), if you want to use
+dual hex-core CPUs (Opteron 2400/8400 series), though only two board
+configurations are believed to support them. Other revisions are
+believed to only support dual quad-core CPUs.
+
+To be sure your board supports a CPU check the official ASUS website here:
+<https://www.asus.com/support/cpu_support>. Note: not all CPUs are listed.
+
+If you are running a Hex-Core CPU on any board version, please contact us.
+
+Board configurations {#configurations}
+==============
+There are 7 different configurations of this board: "standard", 2S, iKVM,
+iKVM/IST, SAS, SAS/iKVM and SAS/iKVM/IST.
+
+The 2S boards have two PCI-E slots with the numbers of lanes shared,
+making each slot have 8 lanes.
+
+The iKVM boards are so called because they offer a remote real-time access
+to the machine through a removable PCI management card, their hardware is
+the same as the non-iKVM ones.
+
+The SAS versions have a 4-port SAS controller and a four 7-pin SAS connectors
+instead of the PCI-E 8x slot which is present in all the other board configurations.
+Note: the SAS functionality is **not supported** by libreboot.
+
+The IST versions with PCB revision 1.05G are the ones who are believed to
+support the six core Opteron Istanbul processors (2400 and 8400 series).
 
 Current issues {#issues}
 ==============
@@ -59,19 +84,25 @@ Current issues {#issues}
     config](http://review.coreboot.org/gitweb?p=board-status.git;a=blob;f=asus/kfsn4-dre/4.0-10101-g039edeb/2015-06-27T03:59:16Z/config.txt;h=4742905c185a93fbda8eb14322dd82c70641aef0;hb=055f5df4e000a97453dfad6c91c2d06ea22b8545)
     doesn't have the issue.
 
--   Text-mode is a bit jittery (but still usable). (the jitter
-    disappears if using KMS, once the kernel starts. The jitter will
-    remain, if booting the kernel in text-mode).
+-   Text-mode is jittery and it may not be usable, so it's recommended
+    to flash the BIOS with the coreboot frame-buffer image (kfsn4-dre_vesafb.rom).
+    The jitter disappears if using KMS once the kernel starts, but it will 
+    remain, if booting the kernel in text-mode.
 
 -   Booting from USB mass storage devices is not possible; neither GRUB
     nor SeaBIOS detect USB drives when present. USB keyboards function
-    under both GRUB and SeaBIOS, albeit slowly under GRUB
-    (several seconds per character typed).
+    under both GRUB and SeaBIOS, albeit slowly under GRUB (several seconds per
+    character typed).
+
+-   To install an operating system you will need a hard disk
+    with a pre-installed OS otherwise you have to plug in another hard disk or
+    a CD/DVD reader in order to boot a copy of the installer of your OS, since
+    the USB booting doesn't work.
 
 Other information
 =================
 
-[specifications](ftp://ftp.sgi.com/public/Technical%20Support/Pdf%20files/Asus/kfsn4-dre.pdf)
+[specifications](https://web.archive.org/web/20181212180051/http://ftp.tekwind.co.jp/pub/asustw/mb/Socket%20F/KFSN4-DRE/Manual/e3335_kfsn4-dre.pdf)
 
 Copyright © 2015 Leah Rowe <info@minifree.org>\