diff --git a/stand/kboot/arch/amd64/load_addr.c b/stand/kboot/arch/amd64/load_addr.c
index cbe066d02d40..fccd17cf8d51 100644
--- a/stand/kboot/arch/amd64/load_addr.c
+++ b/stand/kboot/arch/amd64/load_addr.c
@@ -1,37 +1,162 @@
 /*-
  * Copyright (c) 2022 Netflix, Inc
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2. Redistributions in binary form must reproduce the above copyright
  *    notice, this list of conditions and the following disclaimer in the
  *    documentation and/or other materials provided with the distribution.
  *
  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  * SUCH DAMAGE.
  */
 
 #include <sys/param.h>
 #include <sys/endian.h>
 
 #include "stand.h"
 #include "host_syscall.h"
 #include "kboot.h"
 
+/* Refactor when we do arm64 */
+
+struct memory_segments
+{
+	uint64_t	start;
+	uint64_t	end;
+	uint64_t	type;
+};
+
+enum types {
+	system_ram = 1,
+	acpi_tables,
+	acpi_nv_storage,
+	unusable,
+	persistent_old,
+	persistent,
+	soft_reserved,
+	reserved,
+};
+
+struct kv
+{
+	uint64_t	type;
+	char *		name;
+} str2type_kv[] = {
+	{ system_ram,		"System RAM" },
+	{ acpi_tables,		"ACPI Tables" },
+	{ acpi_nv_storage,	"ACPI Non-volatile Storage" },
+	{ unusable,		"Unusable memory" },
+	{ persistent_old,	"Persistent Memory (legacy)" },
+	{ persistent,		"Persistent Memory" },
+	{ soft_reserved,	"Soft Reserved" },
+	{ reserved,		"reserved" },
+	{ 0, NULL },
+};
+
+#define MEMMAP "/sys/firmware/memmap"
+
+static bool
+str2type(struct kv *kv, const char *buf, uint64_t *value)
+{
+	while (kv->name != NULL) {
+		if (strcmp(kv->name, buf) == 0) {
+			*value = kv->type;
+			return true;
+		}
+		kv++;
+	}
+
+	return false;
+}
+
+static int
+read_memmap(struct memory_segments *segs, int maxseg)
+{
+	int n;
+	char name[MAXPATHLEN];
+	char buf[80];
+
+	n = 0;
+	do {
+		snprintf(name, sizeof(name), "%s/%d/start", MEMMAP, n);
+		if (!file2u64(name, &segs[n].start))
+			break;
+		snprintf(name, sizeof(name), "%s/%d/length", MEMMAP, n);
+		if (!file2u64(name, &segs[n].end))
+			break;
+		snprintf(name, sizeof(name), "%s/%d/type", MEMMAP, n);
+		if (!file2str(name, buf, sizeof(buf)))
+			break;
+		if (!str2type(str2type_kv, buf, &segs[n].type))
+			break;
+		n++;
+	} while (n < maxseg);
+
+	return n;
+}
+
+#define BAD_SEG ~0ULL
+
+#define SZ(s) (((s).end - (s).start) + 1)
+
+static uint64_t
+find_ram(struct memory_segments *segs, int nr_seg, uint64_t minpa, uint64_t align,
+    uint64_t sz, uint64_t maxpa)
+{
+	uint64_t start;
+
+	/* XXX assume segs are sorted in numeric order -- assumed not ensured */
+	for (int i = 0; i < nr_seg; i++) {
+		if (segs[i].type != system_ram ||
+		    SZ(segs[i]) < sz ||
+		    minpa + sz > segs[i].end ||
+		    maxpa < segs[i].start)
+			continue;
+		start = roundup(segs[i].start, align);
+		if (start < minpa)	/* Too small, round up and try again */
+			start = (roundup(minpa, align));
+		if (start + sz > segs[i].end)	/* doesn't fit in seg */
+			continue;
+		if (start > maxpa ||		/* Over the edge */
+		    start + sz > maxpa)		/* on the edge */
+			break;			/* No hope to continue */
+		return start;
+	}
+
+	return BAD_SEG;
+}
+
 uint64_t
 kboot_get_phys_load_segment(void)
 {
-	return (~0ULL);
+	static uint64_t base_seg = BAD_SEG;
+	struct memory_segments segs[32];
+	int nr_seg;
+
+	if (base_seg != BAD_SEG)
+		return (base_seg);
+
+	nr_seg = read_memmap(segs, nitems(segs));
+	if (nr_seg > 0)
+		base_seg = find_ram(segs, nr_seg, 2ULL << 20, 2ULL << 20,
+		    64ULL << 20, 4ULL << 30);
+	if (base_seg == BAD_SEG) {
+		/* XXX Should fall back to using /proc/iomem maybe? */
+		/* XXX PUNT UNTIL I NEED SOMETHING BETTER */
+		base_seg = 42ULL * (1 << 20); /* Jam it in at the odd-ball address of 42MB so it stands out */
+	}
+	return (base_seg);
 }