diff --git a/Documentation/i386/boot.txt b/Documentation/i386/boot.txt
index 6498666..d01b7a2 100644
--- a/Documentation/i386/boot.txt
+++ b/Documentation/i386/boot.txt
@@ -2,7 +2,7 @@
 		     ----------------------------
 
 		    H. Peter Anvin <hpa@zytor.com>
-			Last update 2007-03-06
+			Last update 2007-05-07
 
 On the i386 platform, the Linux kernel uses a rather complicated boot
 convention.  This has evolved partially due to historical aspects, as
@@ -11,7 +11,7 @@
 expectations in the PC industry caused by the effective demise of
 real-mode DOS as a mainstream operating system.
 
-Currently, four versions of the Linux/i386 boot protocol exist.
+Currently, the following versions of the Linux/i386 boot protocol exist.
 
 Old kernels:	zImage/Image support only.  Some very early kernels
 		may not even support a command line.
@@ -183,9 +183,9 @@
 	a version number.  Otherwise, enter 0xFF here.
 
 	Assigned boot loader ids:
-	0  LILO
+	0  LILO			(0x00 reserved for pre-2.00 bootloader)
 	1  Loadlin
-	2  bootsect-loader
+	2  bootsect-loader	(0x20, all other values reserved)
 	3  SYSLINUX
 	4  EtherBoot
 	5  ELILO
@@ -210,6 +210,9 @@
 	additional data (such as the kernel command line) moved in
 	addition to the real-mode kernel itself.
 
+	The unit is bytes starting with the beginning of the boot
+	sector.
+
   ramdisk_image, ramdisk_size:
 	If your boot loader has loaded an initial ramdisk (initrd),
 	set ramdisk_image to the 32-bit pointer to the ramdisk data
@@ -278,14 +281,54 @@
 	field.
 
 
+**** MEMORY LAYOUT OF THE REAL-MODE CODE
+
+The real-mode code requires a stack/heap to be set up, as well as
+memory allocated for the kernel command line.  This needs to be done
+in the real-mode accessible memory in bottom megabyte.
+
+It should be noted that modern machines often have a sizable Extended
+BIOS Data Area (EBDA).  As a result, it is advisable to use as little
+of the low megabyte as possible.
+
+Unfortunately, under the following circumstances the 0x90000 memory
+segment has to be used:
+
+	- When loading a zImage kernel ((loadflags & 0x01) == 0).
+	- When loading a 2.01 or earlier boot protocol kernel.
+
+	  -> For the 2.00 and 2.01 boot protocols, the real-mode code
+	     can be loaded at another address, but it is internally
+	     relocated to 0x90000.  For the "old" protocol, the
+	     real-mode code must be loaded at 0x90000.
+
+When loading at 0x90000, avoid using memory above 0x9a000.
+
+For boot protocol 2.02 or higher, the command line does not have to be
+located in the same 64K segment as the real-mode setup code; it is
+thus permitted to give the stack/heap the full 64K segment and locate
+the command line above it.
+
+The kernel command line should not be located below the real-mode
+code, nor should it be located in high memory.
+
+
 **** SAMPLE BOOT CONFIGURATION
 
 As a sample configuration, assume the following layout of the real
-mode segment (this is a typical, and recommended layout):
+mode segment:
 
-	0x0000-0x7FFF	Real mode kernel
-	0x8000-0x8FFF	Stack and heap
-	0x9000-0x90FF	Kernel command line
+    When loading below 0x90000, use the entire segment:
+
+	0x0000-0x7fff	Real mode kernel
+	0x8000-0xdfff	Stack and heap
+	0xe000-0xffff	Kernel command line
+
+    When loading at 0x90000 OR the protocol version is 2.01 or earlier:
+
+	0x0000-0x7fff	Real mode kernel
+	0x8000-0x97ff	Stack and heap
+	0x9800-0x9fff	Kernel command line
 
 Such a boot loader should enter the following fields in the header:
 
@@ -301,22 +344,33 @@
 			ramdisk_image = <initrd_address>;
 			ramdisk_size = <initrd_size>;
 		}
+
+		if ( protocol >= 0x0202 && loadflags & 0x01 )
+			heap_end = 0xe000;
+		else
+			heap_end = 0x9800;
+
 		if ( protocol >= 0x0201 ) {
-			heap_end_ptr = 0x9000 - 0x200;
+			heap_end_ptr = heap_end - 0x200;
 			loadflags |= 0x80; /* CAN_USE_HEAP */
 		}
+
 		if ( protocol >= 0x0202 ) {
-			cmd_line_ptr = base_ptr + 0x9000;
+			cmd_line_ptr = base_ptr + heap_end;
+			strcpy(cmd_line_ptr, cmdline);
 		} else {
 			cmd_line_magic	= 0xA33F;
-			cmd_line_offset = 0x9000;
-			setup_move_size = 0x9100;
+			cmd_line_offset = heap_end;
+			setup_move_size = heap_end + strlen(cmdline)+1;
+			strcpy(base_ptr+cmd_line_offset, cmdline);
 		}
 	} else {
 		/* Very old kernel */
 
+		heap_end = 0x9800;
+
 		cmd_line_magic	= 0xA33F;
-		cmd_line_offset = 0x9000;
+		cmd_line_offset = heap_end;
 
 		/* A very old kernel MUST have its real-mode code
 		   loaded at 0x90000 */
@@ -324,12 +378,11 @@
 		if ( base_ptr != 0x90000 ) {
 			/* Copy the real-mode kernel */
 			memcpy(0x90000, base_ptr, (setup_sects+1)*512);
-			/* Copy the command line */
-			memcpy(0x99000, base_ptr+0x9000, 256);
-
 			base_ptr = 0x90000;		 /* Relocated */
 		}
 
+		strcpy(0x90000+cmd_line_offset, cmdline);
+
 		/* It is recommended to clear memory up to the 32K mark */
 		memset(0x90000 + (setup_sects+1)*512, 0,
 		       (64-(setup_sects+1))*512);
@@ -375,10 +428,11 @@
 	line is parsed.
 
   mem=<size>
-	<size> is an integer in C notation optionally followed by K, M
-	or G (meaning << 10, << 20 or << 30).  This specifies the end
-	of memory to the kernel. This affects the possible placement
-	of an initrd, since an initrd should be placed near end of
+	<size> is an integer in C notation optionally followed by
+	(case insensitive) K, M, G, T, P or E (meaning << 10, << 20,
+	<< 30, << 40, << 50 or << 60).  This specifies the end of
+	memory to the kernel. This affects the possible placement of
+	an initrd, since an initrd should be placed near end of
 	memory.  Note that this is an option to *both* the kernel and
 	the bootloader!
 
@@ -428,7 +482,7 @@
 
 	/* Set up the real-mode kernel stack */
 	_SS = seg;
-	_SP = 0x9000;	/* Load SP immediately after loading SS! */
+	_SP = heap_end;
 
 	_DS = _ES = _FS = _GS = seg;
 	jmp_far(seg+0x20, 0);	/* Run the kernel */
@@ -460,8 +514,9 @@
   code32_start:
 	A 32-bit flat-mode routine *jumped* to immediately after the
 	transition to protected mode, but before the kernel is
-	uncompressed.  No segments, except CS, are set up; you should
-	set them up to KERNEL_DS (0x18) yourself.
+	uncompressed.  No segments, except CS, are guaranteed to be
+	set up (current kernels do, but older ones do not); you should
+	set them up to BOOT_DS (0x18) yourself.
 
 	After completing your hook, you should jump to the address
 	that was in this field before your boot loader overwrote it.