diff --git a/src/arch/i386/firmware/pcbios/fakee820.c b/src/arch/i386/firmware/pcbios/fakee820.c
new file mode 100644
index 00000000..e171edfd
--- /dev/null
+++ b/src/arch/i386/firmware/pcbios/fakee820.c
@@ -0,0 +1,90 @@
+/* Copyright (C) 2008 Michael Brown <mbrown@fensystems.co.uk>.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License as
+ * published by the Free Software Foundation; either version 2 of the
+ * License, or any later version.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+ */
+
+#include <realmode.h>
+#include <biosint.h>
+
+/** Assembly routine in inline asm */
+extern void int15_fakee820();
+
+/** Original INT 15 handler */
+static struct segoff __text16 ( real_int15_vector );
+#define real_int15_vector __use_text16 ( real_int15_vector )
+
+/** An INT 15,e820 memory map entry */
+struct e820_entry {
+	/** Start of region */
+	uint64_t start;
+	/** Length of region */
+	uint64_t len;
+	/** Type of region */
+	uint32_t type;
+} __attribute__ (( packed ));
+
+#define E820_TYPE_RAM		1 /**< Normal memory */
+#define E820_TYPE_RSVD		2 /**< Reserved and unavailable */
+#define E820_TYPE_ACPI		3 /**< ACPI reclaim memory */
+#define E820_TYPE_NVS		4 /**< ACPI NVS memory */
+
+/** Fake e820 map */
+static struct e820_entry __text16_array ( e820map, [] ) __used = {
+	{ 0x00000000ULL, ( 0x000a0000ULL - 0x00000000ULL ), E820_TYPE_RAM },
+	{ 0x00100000ULL, ( 0xcfb50000ULL - 0x00100000ULL ), E820_TYPE_RAM },
+	{ 0xcfb50000ULL, ( 0xcfb64000ULL - 0xcfb50000ULL ), E820_TYPE_RSVD },
+	{ 0xcfb64000ULL, ( 0xcfb66000ULL - 0xcfb64000ULL ), E820_TYPE_RSVD },
+	{ 0xcfb66000ULL, ( 0xcfb85c00ULL - 0xcfb66000ULL ), E820_TYPE_ACPI },
+	{ 0xcfb85c00ULL, ( 0xd0000000ULL - 0xcfb85c00ULL ), E820_TYPE_RSVD },
+	{ 0xe0000000ULL, ( 0xf0000000ULL - 0xe0000000ULL ), E820_TYPE_RSVD },
+	{ 0xfe000000ULL, (0x100000000ULL - 0xfe000000ULL ), E820_TYPE_RSVD },
+	{0x100000000ULL, (0x230000000ULL -0x100000000ULL ), E820_TYPE_RAM },
+};
+#define e820map __use_text16 ( e820map )
+
+void fake_e820 ( void ) {
+	__asm__ __volatile__ (
+		TEXT16_CODE ( "\nint15_fakee820:\n\t"
+			      "pushfw\n\t"
+			      "cmpl $0xe820, %%eax\n\t"
+			      "jne 99f\n\t"
+			      "cmpl $0x534d4150, %%edx\n\t"
+			      "jne 99f\n\t"
+			      "pushaw\n\t"
+			      "leaw e820map(%%bx), %%si\n\t"
+			      "cs rep movsb\n\t"
+			      "popaw\n\t"
+			      "movl %%edx, %%eax\n\t"
+			      "addl $20, %%ebx\n\t"
+			      "cmpl %0, %%ebx\n\t"
+			      "jne 1f\n\t"
+			      "xorl %%ebx,%%ebx\n\t"
+			      "\n1:\n\t"
+			      "popfw\n\t"
+			      "clc\n\t"
+			      "lret $2\n\t"
+			      "\n99:\n\t"
+			      "popfw\n\t"
+			      "ljmp *%%cs:real_int15_vector\n\t" )
+		: : "i" ( sizeof ( e820map ) ) );
+
+	hook_bios_interrupt ( 0x15, ( unsigned int ) int15_fakee820,
+			      &real_int15_vector );
+}
+
+void unfake_e820 ( void ) {
+	unhook_bios_interrupt ( 0x15, ( unsigned int ) int15_fakee820,
+				&real_int15_vector );
+}
diff --git a/src/arch/i386/firmware/pcbios/hidemem.c b/src/arch/i386/firmware/pcbios/hidemem.c
index 202081b6..c9df7bd0 100644
--- a/src/arch/i386/firmware/pcbios/hidemem.c
+++ b/src/arch/i386/firmware/pcbios/hidemem.c
@@ -19,10 +19,14 @@
 #include <realmode.h>
 #include <biosint.h>
 #include <basemem.h>
+#include <fakee820.h>
 #include <gpxe/init.h>
 #include <gpxe/memmap.h>
 #include <gpxe/hidemem.h>
 
+/** Set to true if you want to test a fake E820 map */
+#define FAKE_E820 0
+
 /** Alignment for hidden memory regions */
 #define ALIGN_HIDDEN 4096   /* 4kB page alignment should be enough */
 
@@ -135,6 +139,13 @@ static void hide_etherboot ( void ) {
 	DBG ( "Hiding gPXE from system memory map\n" );
 	get_memmap ( &memmap );
 
+	/* Hook in fake E820 map, if we're testing one */
+	if ( FAKE_E820 ) {
+		DBG ( "Hooking in fake E820 map\n" );
+		fake_e820();
+		get_memmap ( &memmap );
+	}
+
 	/* Initialise the hidden regions */
 	hide_basemem();
 	hide_umalloc ( virt_to_phys ( _text ), virt_to_phys ( _text ) );
@@ -194,6 +205,10 @@ static void unhide_etherboot ( int flags __unused ) {
 	 */
 	unhook_bios_interrupt ( 0x15, ( unsigned int ) int15,
 				&int15_vector );
+
+	/* Unhook fake E820 map, if used */
+	if ( FAKE_E820 )
+		unfake_e820();
 }
 
 /** Hide Etherboot startup function */
diff --git a/src/arch/i386/include/fakee820.h b/src/arch/i386/include/fakee820.h
new file mode 100644
index 00000000..f1fe8aff
--- /dev/null
+++ b/src/arch/i386/include/fakee820.h
@@ -0,0 +1,7 @@
+#ifndef _FAKEE820_H
+#define _FAKEE820_H
+
+extern void fake_e820 ( void );
+extern void unfake_e820 ( void );
+
+#endif /* _FAKEE820_H */