--- /n/sources/plan9/sys/src/9k/k10/fns.h	Thu Sep 24 10:29:32 2026
+++ /sys/src/9k/k10/fns.h	Thu Sep 24 00:00:00 2026
@@ -23,6 +23,7 @@ u32int	cpuid(u32int, u32int, u32int[4]);
 int	dbgprint(char*, ...);
 #define decref(r)	adec(&(r)->ref)
 void	delay(int);
+int	e820(void);
 #define	evenaddr(x)				/* x86 doesn't care */
 int	fpudevprocio(Proc*, void*, long, uintptr, int);
 void	fpuinit(void);
--- /n/sources/plan9/sys/src/9k/k10/main.c	Thu Sep 24 10:29:32 2026
+++ /sys/src/9k/k10/main.c	Thu Sep 24 00:00:00 2026
@@ -192,9 +192,11 @@ main(u32int ax, u32int bx)
 	up = nil;
 
 	asminit();
-	multiboot(ax, bx, 0);
+	i = multiboot(ax, bx, 0);
 	options(oargc, oargv);
 	crapoptions();
+	if(i < 0)
+		e820();
 
 	/*
 	 * Need something for initial delays
--- /n/sources/plan9/sys/src/9k/k10/multiboot.c	Thu Sep 24 10:29:32 2026
+++ /sys/src/9k/k10/multiboot.c	Thu Sep 24 00:00:00 2026
@@ -149,3 +149,34 @@ multiboot(u32int magic, u32int pmbi, int vflag)
 
 	return 0;
 }
+
+int
+e820(void)
+{
+	char *s;
+	int type;
+	u64int base, top;
+
+	if((s = getconf("*e820")) == nil)
+		return -1;
+	for(;;){
+		while(*s == ' ')
+			s++;
+		if(*s == 0)
+			break;
+		type = 1;
+		if(s[1] == ' '){
+			type = s[0] - '0';
+			s += 2;
+		}
+		base = strtoull(s, &s, 16);
+		if(*s != ' ')
+			break;
+		top = strtoull(s, &s, 16);
+		if(*s != ' ' && *s != 0)
+			break;
+		if(base < top && type >= 1 && type <= 4)
+			asmmapinit(base, top-base, type);
+	}
+	return 0;
+}
--- /n/sources/plan9/sys/man/8/plan9.ini	Fri May 11 10:50:09 2012
+++ /sys/man/8/plan9.ini	Thu Sep 24 00:00:00 2026
@@ -757,6 +757,11 @@ This variable disables such switches.
 .SS \fL*noe820scan=\fP
 When available, the PC kernel uses the BIOS E820 memory map
 to size memory.  This variable disables the scan.
+.SS \fL*e820=\fItype base top ...
+.IR 9boot (8)
+passes the BIOS E820 memory map in this variable:
+a type, a base address and a top address, in hexadecimal, for each range.
+The 9k kernel sizes memory from it when not started by a multiboot loader.
 .SS \fL*maxmem=\fIaddress
 This defines the maximum physical address that the system will scan when sizing memory.
 By default the PC operating system will scan up to 3.75 gigabytes