diff --git a/sys/dev/md/md.c b/sys/dev/md/md.c
--- a/sys/dev/md/md.c
+++ b/sys/dev/md/md.c
@@ -280,7 +280,9 @@
 		/* MD_PRELOAD related fields */
 		struct {
 			u_char *pl_ptr;
+			vm_paddr_t pl_phys;
 			size_t pl_len;
+			bool mapped;
 			char name[PATH_MAX];
 		} s_preload;
 
@@ -822,7 +824,8 @@
 }
 
 static void
-mdcopyto_vlist(void *src, bus_dma_segment_t *vlist, off_t offset, off_t len)
+mdcopyto_vlist(struct md_s *sc, void *src, vm_paddr_t psrc,
+    bus_dma_segment_t *vlist, off_t offset, off_t len)
 {
 	off_t seg_len;
 
@@ -833,8 +836,14 @@
 
 	while (len != 0) {
 		seg_len = omin(len, vlist->ds_len - offset);
-		bcopy(src, (void *)(uintptr_t)(vlist->ds_addr + offset),
-		    seg_len);
+		if (sc->s_preload.mapped) {
+			bcopy(src, (void *)(uintptr_t)(vlist->ds_addr + offset),
+			    seg_len);
+		} else {
+			physcopyout(psrc,
+			    (void *)(uintptr_t)(vlist->ds_addr + offset),
+			    seg_len);
+		}
 		offset = 0;
 		src = (uint8_t *)src + seg_len;
 		len -= seg_len;
@@ -843,7 +852,8 @@
 }
 
 static void
-mdcopyfrom_vlist(bus_dma_segment_t *vlist, off_t offset, void *dst, off_t len)
+mdcopyfrom_vlist(struct md_s *sc, bus_dma_segment_t *vlist, off_t offset,
+    void *dst, vm_paddr_t pdst, off_t len)
 {
 	off_t seg_len;
 
@@ -854,8 +864,13 @@
 
 	while (len != 0) {
 		seg_len = omin(len, vlist->ds_len - offset);
-		bcopy((void *)(uintptr_t)(vlist->ds_addr + offset), dst,
-		    seg_len);
+		if (sc->s_preload.mapped) {
+			bcopy((void *)(uintptr_t)(vlist->ds_addr + offset),
+			    dst, seg_len);
+		} else {
+			physcopyin((void *)(uintptr_t)(vlist->ds_addr + offset),
+			    pdst, seg_len);
+		}
 		offset = 0;
 		dst = (uint8_t *)dst + seg_len;
 		len -= seg_len;
@@ -866,25 +881,36 @@
 static int
 mdstart_preload(struct md_s *sc, struct bio *bp)
 {
-	uint8_t *p;
+	uint8_t *p = 0;
+	vm_paddr_t phys = 0;
 
-	p = sc->s_preload.pl_ptr + bp->bio_offset;
+	if (sc->s_preload.mapped)
+		p = sc->s_preload.pl_ptr + bp->bio_offset;
+	else
+		phys = sc->s_preload.pl_phys + bp->bio_offset;
 	switch (bp->bio_cmd) {
 	case BIO_READ:
 		if ((bp->bio_flags & BIO_VLIST) != 0) {
-			mdcopyto_vlist(p, (bus_dma_segment_t *)bp->bio_data,
+			mdcopyto_vlist(sc, p, phys,
+			    (bus_dma_segment_t *)bp->bio_data,
 			    bp->bio_ma_offset, bp->bio_length);
 		} else {
-			bcopy(p, bp->bio_data, bp->bio_length);
+			if (sc->s_preload.mapped)
+				bcopy(p, bp->bio_data, bp->bio_length);
+			else
+				physcopyout(phys, bp->bio_data, bp->bio_length);
 		}
 		cpu_flush_dcache(bp->bio_data, bp->bio_length);
 		break;
 	case BIO_WRITE:
 		if ((bp->bio_flags & BIO_VLIST) != 0) {
-			mdcopyfrom_vlist((bus_dma_segment_t *)bp->bio_data,
-			    bp->bio_ma_offset, p, bp->bio_length);
+			mdcopyfrom_vlist(sc, (bus_dma_segment_t *)bp->bio_data,
+			    bp->bio_ma_offset, p, phys, bp->bio_length);
 		} else {
-			bcopy(bp->bio_data, p, bp->bio_length);
+			if (sc->s_preload.mapped)
+				bcopy(bp->bio_data, p, bp->bio_length);
+			else
+				physcopyin(bp->bio_data, phys, bp->bio_length);
 		}
 		break;
 	}
@@ -2043,7 +2069,8 @@
 }
 
 static void
-md_preloaded(u_char *image, size_t length, const char *name)
+md_preloaded(u_char *image, vm_paddr_t pimage, size_t length,
+    const char *name, bool mapped)
 {
 	struct md_s *sc;
 	int error;
@@ -2054,7 +2081,9 @@
 	sc->mediasize = length;
 	sc->sectorsize = DEV_BSIZE;
 	sc->s_preload.pl_ptr = image;
+	sc->s_preload.pl_phys = pimage;
 	sc->s_preload.pl_len = length;
+	sc->s_preload.mapped = mapped;
 	sc->start = mdstart_preload;
 	if (name != NULL)
 		strlcpy(sc->s_preload.name, name,
@@ -2101,10 +2130,10 @@
 	if (mfs_root_size != 0) {
 		sx_xlock(&md_sx);
 #ifdef MD_ROOT_MEM
-		md_preloaded(mfs_root, mfs_root_size, NULL);
+		md_preloaded(mfs_root, 0, mfs_root_size, NULL, true);
 #else
-		md_preloaded(__DEVOLATILE(u_char *, &mfs_root), mfs_root_size,
-		    NULL);
+		md_preloaded(__DEVOLATILE(u_char *, &mfs_root), 0,
+		    mfs_root_size, NULL, true);
 #endif
 		sx_xunlock(&md_sx);
 	}
@@ -2123,7 +2152,7 @@
 		len = preload_fetch_size(mod);
 		if (ptr != NULL && len != 0) {
 			sx_xlock(&md_sx);
-			md_preloaded(ptr, len, name);
+			md_preloaded(ptr, 0, len, name, true);
 			sx_xunlock(&md_sx);
 		}
 	}
@@ -2136,14 +2165,11 @@
 			(long *) &paddr) != 0 ||
 		    resource_int_value("md", i, "len", &len) != 0)
 		        break;
-		ptr = (char *)pmap_map(NULL, paddr, paddr + len, VM_PROT_READ);
-		if (ptr != NULL && len != 0) {
-			sprintf(scratch, "preload%d 0x%016jx", i,
-			    (uintmax_t)paddr);
-			sx_xlock(&md_sx);
-			md_preloaded(ptr, len, scratch);
-			sx_xunlock(&md_sx);
-		}
+		sprintf(scratch, "preload%d 0x%016jx", i,
+		    (uintmax_t)paddr);
+		sx_xlock(&md_sx);
+		md_preloaded(0, paddr, len, scratch, false);
+		sx_xunlock(&md_sx);
 	}
 
 	status_dev = make_dev(&mdctl_cdevsw, INT_MAX, UID_ROOT, GID_WHEEL,