--- ./gpxe_src/src/arch/i386/prefix/romprefix.S	2010-01-18 21:06:58.000000000 -0500
+++ ./gpxe_src.int18/src/arch/i386/prefix/romprefix.S	2010-01-20 11:19:31.000000000 -0500
@@ -145,7 +145,7 @@
  * Determine whether or not this is a PnP system via a signature
  * check.  If it is PnP, return to the PnP BIOS indicating that we are
  * a boot-capable device; the BIOS will call our boot execution vector
- * if it wants to boot us.  If it is not PnP, hook INT 19.
+ * if it wants to boot us.  If it is not PnP, hook INT 18.
  */
 init:
 	/* Preserve registers, clear direction flag, set %ds=%cs */
@@ -273,19 +273,17 @@
 	testw	%ax, %ax
 	je	got_bbs
 no_pnp:	/* Not PnP-compliant - therefore cannot be BBS-compliant */
-no_bbs:	/* Not BBS-compliant - must hook INT 19 */
-	movw	$init_message_int19, %si
+no_bbs:	/* Not BBS-compliant - hooking INT 18 */
+	movw	$init_message_int18, %si
 	xorw	%di, %di
 	call	print_message
 	xorw	%ax, %ax
 	movw	%ax, %es
-	pushl	%es:( 0x19 * 4 )
-	popl	orig_int19
 	pushw	%gs /* %gs contains runtime %cs */
-	pushw	$int19_entry
-	popl	%es:( 0x19 * 4 )
+	pushw	$int18_entry
+	popl	%es:( 0x18 * 4 )
 	jmp	bbs_done
-got_bbs: /* BBS compliant - no need to hook INT 19 */
+got_bbs: /* BBS compliant - no need to hook INT 18 */
 	movw	$init_message_bbs, %si
 	xorw	%di, %di
 	call	print_message
@@ -470,9 +468,9 @@
 init_message_pmm:
 	.asciz	" PMM"
 	.size	init_message_pmm, . - init_message_pmm
-init_message_int19:
-	.asciz	" INT19"
-	.size	init_message_int19, . - init_message_int19
+init_message_int18:
+	.asciz	" INT18"
+	.size	init_message_int18, . - init_message_int18
 init_message_prompt:
 	.asciz	"\nPress Ctrl-B to configure "
 	.size	init_message_prompt, . - init_message_prompt
@@ -517,59 +515,30 @@
 	lret
 	.size	bev_entry, . - bev_entry
 
-/* INT19 entry point
+/* INT18 entry point
  *
- * Called via the hooked INT 19 if we detected a non-PnP BIOS.  We
- * attempt to return via the original INT 19 vector (if we were able
- * to store it).
+ * Called via the hooked INT 18 if we detected a non-PnP BIOS.  
+ * Use iret to return to firmware
  */
-int19_entry:
-	pushw	%cs
-	popw	%ds
-	/* Prompt user to press B to boot */
-	movw	$int19_message_prompt, %si
-	xorw	%di, %di
-	call	print_message
-	movw	$prodstr, %si
-	call	print_message
-	movw	$int19_message_dots, %si
-	call	print_message
-	movw	$0xdf4e, %bx
-	call	wait_for_key
-	pushf
-	xorw	%di, %di
-	call	print_kill_line
-	movw	$int19_message_done, %si
-	call	print_message
-	popf
-	jz	1f
-	/* Leave keypress in buffer and start gPXE.  The keypress will
-	 * cause the usual initial Ctrl-B prompt to be skipped.
-	 */
+int18_entry:
+    pushfl
+    pushal
+    pushw   %gs
+    pushw   %fs
+    pushw   %es
+    pushw   %ds
+
 	pushw	%cs
 	call	exec
-1:	/* Try to call original INT 19 vector */
-	movl	%cs:orig_int19, %eax
-	testl	%eax, %eax
-	je	2f
-	ljmp	*%cs:orig_int19
-2:	/* No chained vector: issue INT 18 as a last resort */
-	int	$0x18
-	.size	int19_entry, . - int19_entry
-orig_int19:
-	.long	0
-	.size	orig_int19, . - orig_int19
 
-int19_message_prompt:
-	.asciz	"Press N to skip booting from "
-	.size	int19_message_prompt, . - int19_message_prompt
-int19_message_dots:
-	.asciz	"..."
-	.size	int19_message_dots, . - int19_message_dots
-int19_message_done:
-	.asciz	"\n\n"
-	.size	int19_message_done, . - int19_message_done
-	
+    popw    %ds
+    popw    %es
+    popw    %fs
+    popw    %gs
+    popal
+    popfl
+    iret
+
 /* Execute as a boot device
  *
  */