--- wikisrc/users/rkujawa/g-rex.mdwn	2012/07/07 11:27:29	1.7
+++ wikisrc/users/rkujawa/g-rex.mdwn	2012/07/08 12:30:39	1.8
@@ -19,25 +19,46 @@ In case you've noticed an error in this 
 
 # 1. Theory of operation
 
-G-REX is connected to local expansion slot present on CyberStorm PPC and 
-Blizzard PPC.  
+# 1a. Hardware 
 
-G-REX is an evolution of PCI bridge used previously on CyberVisionPPC and 
-BlizzardVisionPPC cards. These products share a lot of similiarities (at 
-least when it comes to PCI interface). In fact CVPPC/BVPPC can be treated as
-a special one-slot version of G-REX. Maybe actually it's the other way around
-;-). 
+Three versions of G-REX exist:
 
-Firmware does the dirty job of assigning PCI resources (BARs, interrupt lines, 
-etc.) before the OS is running. Therefore G-REX does not need any special 
-initialization.
+* G-REX 1200 (for Amiga 1200 equipped with BlizzardPPC)
+* G-REX 4000D (for Amiga 4000 equipped with CyberStormPPC)
+* G-REX 4000T (for Amiga 4000T equipped with CyberStormPPC)
+
+There were at least two different revisions of G-REX 1200. Later revision 
+(marked "Neue Version") probably does support DMA in first two slots. I'm not 
+sure if it is possible to detect revision of the G-REX in software.
+
+Blizzard PPC hardware revision 0 is not compatible with G-REX
+(revision 2 is certainly compatible, not sure about revision 1). 
+
+There's a rumor that most G-REX 4000T were recalled due to hardware problem.
+
+G-REX is connected to local expansion slot present on CyberStorm PPC and 
+Blizzard PPC. These slots have different physical connectors but signals seem 
+to be mostly the same.
+
+The bridge itself is an evolution of PCI bridge used previously on 
+CyberVisionPPC and BlizzardVisionPPC cards. These products share a lot of 
+similiarities (at least when it comes to PCI interface). In fact CVPPC/BVPPC 
+can be treated as a special one-slot version of G-REX. Maybe actually it's the 
+other way around ;-). 
 
 All memory spaces of G-REX are directly visible and addressable in Amiga memory
 space, unlike in Mediator. Firmware allocates memory space as needed, depending
 on what cards are installed.
 
-Blizzard PPC hardware revision 0 is not compatible with G-REX
-(which revisions are compatible?). 
+# 1b. Firmware
+
+G-REX firmware is a part of Flash ROM present on Blizzard PPC and CyberStorm
+PPC boards. Known CSPPC firmware revisions supporting G-REX include 44.69 and 
+44.71.
+
+It does the dirty job of assigning PCI resources (BARs, interrupt lines, 
+etc.) before the OS is running. Therefore G-REX does not need any special 
+initialization.
 
 # 2. Memory map
 
@@ -89,7 +110,7 @@ Addresses in this space are treated as a
 
 On CVPPC/BVPPC this space is present at different address - 0xE0000000.
 
-# 2d. Bridge configuration registers
+# 2d. Bridge configuration registers (0xFFFE0000)
 
 Offset - meaning
 
@@ -102,9 +123,8 @@ properly by the firmware.
 
 # 3. Detecting the G-REX
 
-Since AutoConf entries are created by the firmware, G-REX needs a special 
-firmware for CyberStorm PPC and Blizzard PPC. Known CSPPC firmware revisions 
-supporting G-REX include 44.69 and 44.71.
+Since AutoConf entries are created by the firmware, it is not possible to
+detect G-REX easily if the correct firmware is not installed.
 
 Detecting the G-REX is done by looking for Phase5 vendor ID (8512) and product
 ID 101. Keep in mind that there will be more than one such board present, as
@@ -141,9 +161,6 @@ reverse engineering.
 
 [TO BE COMPLETED]
 
-There were at least two different revisions of G-REX 1200. Later revision 
-probably does support DMA in first two slots. I'm not sure if it is possible
-to detect revision of the G-REX in software.
 
 G-REX 4000D probably has busmaster DMA capability in all slots.