diff --git a/sys/src/9/pc64/l.s b/sys/src/9/pc64/l.s
index 18c6f7320..a1c17aa91 100644
--- a/sys/src/9/pc64/l.s
+++ b/sys/src/9/pc64/l.s
@@ -30,6 +30,49 @@ TEXT _protected<>(SB), 1, $-4
 
 	pFARJMP32(SELECTOR(3, SELGDT, 0), _warp64<>-KZERO(SB))
 
+	BYTE	$0x90	/* align */
+
+/*
+ * Must be 4-byte aligned.
+ */
+TEXT _multibootheader<>(SB), 1, $-4
+	LONG	$0x1BADB002			/* magic */
+	LONG	$0x00010003			/* flags */
+	LONG	$-(0x1BADB002 + 0x00010003)	/* checksum */
+	LONG	$_multibootheader<>-KZERO(SB)	/* header_addr */
+	LONG	$_protected<>-KZERO(SB)		/* load_addr */
+	LONG	$edata-KZERO(SB)		/* load_end_addr */
+	LONG	$end-KZERO(SB)			/* bss_end_addr */
+	LONG	$_multibootentry<>-KZERO(SB)	/* entry_addr */
+	LONG	$0				/* mode_type */
+	LONG	$0				/* width */
+	LONG	$0				/* height */
+	LONG	$0				/* depth */
+
+/* 
+ * the kernel expects the data segment to be page-aligned
+ * multiboot bootloaders put the data segment right behind text
+ */
+TEXT _multibootentry<>(SB), 1, $-4
+	MOVL	$etext-KZERO(SB), SI
+	MOVL	SI, DI
+	ADDL	$(BY2PG-1), DI
+	ANDL	$~(BY2PG-1), DI
+	MOVL	$edata-KZERO(SB), CX
+	SUBL	DI, CX
+	ADDL	CX, SI
+	ADDL	CX, DI
+	STD
+	REP; MOVSB
+	CLD
+	MOVL	BX, multibootptr-KZERO(SB)
+	MOVL	$_protected<>-KZERO(SB), AX
+	JMP*	AX
+
+/* multiboot structure pointer (physical address) */
+TEXT multibootptr(SB), 1, $-4
+	LONG	$0
+
 TEXT _gdt<>(SB), 1, $-4
 	/* null descriptor */
 	LONG	$0
diff --git a/sys/src/9/pc64/main.c b/sys/src/9/pc64/main.c
index 9cec7f8f9..f3f94e5b2 100644
--- a/sys/src/9/pc64/main.c
+++ b/sys/src/9/pc64/main.c
@@ -32,13 +32,62 @@ uchar *sp;	/* user stack of init proc */
 
 extern void (*i8237alloc)(void);
 
+static void
+multibootargs(void)
+{
+	extern ulong multibootptr;
+	ulong *multiboot;
+	char *cp, *ep;
+	ulong *m, l;
+
+	if(multibootptr == 0)
+		return;
+
+	multiboot = (ulong*)KADDR(multibootptr);
+	/* command line */
+	if((multiboot[0] & (1<<2)) != 0)
+		strncpy(BOOTLINE, KADDR(multiboot[4]), BOOTLINELEN-1);
+
+	cp = BOOTARGS;
+	ep = cp + BOOTARGSLEN-1;
+
+	/* memory map */
+	if((multiboot[0] & (1<<6)) != 0 && (l = multiboot[11]) >= 24){
+		cp = seprint(cp, ep, "*e820=");
+		m = KADDR(multiboot[12]);
+		while(m[0] >= 20 && m[0] <= l-4){
+			uvlong base, size;
+			m++;
+			base = ((uvlong)m[0] | (uvlong)m[1]<<32);
+			size = ((uvlong)m[2] | (uvlong)m[3]<<32);
+			cp = seprint(cp, ep, "%.1lux %.16llux %.16llux ",
+				m[4] & 0xF, base, base+size);
+			l -= m[-1]+4;
+			m = (ulong*)((uintptr)m + m[-1]);
+		}
+		cp[-1] = '\n';
+	}
+
+	/* plan9.ini passed as the first module */
+	if((multiboot[0] & (1<<3)) != 0 && multiboot[5] > 0){
+		m = KADDR(multiboot[6]);
+		l = m[1] - m[0];
+		m = KADDR(m[0]);
+		if(cp+l > ep)
+			l = ep - cp;
+		memmove(cp, m, l);
+		cp += l;
+	}
+	*cp = 0;
+}
+
 static void
 options(void)
 {
 	long i, n;
 	char *cp, *line[MAXCONF], *p, *q;
 
-	// multibootargs();
+	multibootargs();
 
 	/*
 	 *  parse configuration args from dos file plan9.ini