diff --git a/sys/amd64/include/minidump.h b/sys/amd64/include/minidump.h
index 1ea92b7..ebdb865 100644
--- a/sys/amd64/include/minidump.h
+++ b/sys/amd64/include/minidump.h
@@ -30,14 +30,14 @@
 #define	_MACHINE_MINIDUMP_H_ 1
 
 #define	MINIDUMP_MAGIC		"minidump FreeBSD/amd64"
-#define	MINIDUMP_VERSION	1
+#define	MINIDUMP_VERSION	2
 
 struct minidumphdr {
 	char magic[24];
 	uint32_t version;
 	uint32_t msgbufsize;
 	uint32_t bitmapsize;
-	uint32_t ptesize;
+	uint32_t pdesize;
 	uint64_t kernbase;
 	uint64_t dmapbase;
 	uint64_t dmapend;
diff --git a/sys/amd64/amd64/minidump_machdep.c b/sys/amd64/amd64/minidump_machdep.c
index a9af809..8fc4ba2 100644
--- a/sys/amd64/amd64/minidump_machdep.c
+++ b/sys/amd64/amd64/minidump_machdep.c
@@ -65,6 +65,7 @@ static off_t dumplo;
 static size_t fragsz;
 static void *dump_va;
 static size_t counter, progress;
+static int bitmap_frozen = 0;
 
 CTASSERT(sizeof(*vm_page_dump) == 8);
 
@@ -167,63 +168,69 @@ blk_write(struct dumperinfo *di, char *ptr, vm_paddr_t pa, size_t sz)
 }
 
 /* A fake page table page, to avoid having to handle both 4K and 2M pages */
-static pt_entry_t fakept[NPTEPG];
+static pd_entry_t fakepd[NPDEPG];
 
 void
 minidumpsys(struct dumperinfo *di)
 {
 	uint64_t dumpsize;
-	uint32_t ptesize;
+	uint32_t pdesize;
 	vm_offset_t va;
 	int error;
 	uint64_t bits;
 	uint64_t *pdp, *pd, *pt, pa;
-	int i, j, k, bit;
+	int i, j, k, n, bit;
 	struct minidumphdr mdhdr;
 
 	counter = 0;
 	/* Walk page table pages, set bits in vm_page_dump */
-	ptesize = 0;
+	pdesize = 0;
 	pdp = (uint64_t *)PHYS_TO_DMAP(KPDPphys);
 	for (va = VM_MIN_KERNEL_ADDRESS; va < MAX(KERNBASE + NKPT * NBPDR,
-	    kernel_vm_end); va += NBPDR) {
+	    kernel_vm_end); ) {
 		i = (va >> PDPSHIFT) & ((1ul << NPDPEPGSHIFT) - 1);
 		/*
 		 * We always write a page, even if it is zero. Each
-		 * page written corresponds to 2MB of space
+		 * page written corresponds to 1GB of space
 		 */
-		ptesize += PAGE_SIZE;
-		if ((pdp[i] & PG_V) == 0)
-			continue;
-		pd = (uint64_t *)PHYS_TO_DMAP(pdp[i] & PG_FRAME);
-		j = ((va >> PDRSHIFT) & ((1ul << NPDEPGSHIFT) - 1));
-		if ((pd[j] & (PG_PS | PG_V)) == (PG_PS | PG_V))  {
-			/* This is an entire 2M page. */
-			pa = pd[j] & PG_PS_FRAME;
-			for (k = 0; k < NPTEPG; k++) {
-				if (is_dumpable(pa))
-					dump_add_page(pa);
-				pa += PAGE_SIZE;
-			}
+		pdesize += PAGE_SIZE;
+		if ((pdp[i] & PG_V) == 0) {
+			va += NBPDP;
 			continue;
 		}
-		if ((pd[j] & PG_V) == PG_V) {
-			/* set bit for each valid page in this 2MB block */
-			pt = (uint64_t *)PHYS_TO_DMAP(pd[j] & PG_FRAME);
-			for (k = 0; k < NPTEPG; k++) {
-				if ((pt[k] & PG_V) == PG_V) {
-					pa = pt[k] & PG_FRAME;
+
+		pd = (uint64_t *)PHYS_TO_DMAP(pdp[i] & PG_FRAME);
+		for (n = 0; n < NPDEPG; n++, va += NBPDR) {
+			j = ((va >> PDRSHIFT) & ((1ul << NPDEPGSHIFT) - 1));
+			if ((pd[j] & (PG_PS | PG_V)) == (PG_PS | PG_V))  {
+				/* This is an entire 2M page. */
+				pa = pd[j] & PG_PS_FRAME;
+				for (k = 0; k < NPTEPG; k++) {
 					if (is_dumpable(pa))
 						dump_add_page(pa);
+					pa += PAGE_SIZE;
+				}
+				continue;
+			}
+			if ((pd[j] & PG_V) == PG_V) {
+				pa = pd[j] & PG_FRAME;
+				if (is_dumpable(pa))
+					dump_add_page(pa);
+				/* set bit for each valid page in this 2MB block */
+				pt = (uint64_t *)PHYS_TO_DMAP(pd[j] & PG_FRAME);
+				for (k = 0; k < NPTEPG; k++) {
+					if ((pt[k] & PG_V) == PG_V) {
+						pa = pt[k] & PG_FRAME;
+						if (is_dumpable(pa))
+							dump_add_page(pa);
+					}
 				}
 			}
-		} else {
-			/* nothing, we're going to dump a null page */
 		}
 	}
 
 	/* Calculate dump size. */
-	dumpsize = ptesize;
+	dumpsize = pdesize;
 	dumpsize += round_page(msgbufp->msg_size);
 	dumpsize += round_page(vm_page_dump_size);
 	for (i = 0; i < vm_page_dump_size / sizeof(*vm_page_dump); i++) {
@@ -257,7 +264,7 @@ minidumpsys(struct dumperinfo *di)
 	mdhdr.version = MINIDUMP_VERSION;
 	mdhdr.msgbufsize = msgbufp->msg_size;
 	mdhdr.bitmapsize = vm_page_dump_size;
-	mdhdr.ptesize = ptesize;
+	mdhdr.pdesize = pdesize;
 	mdhdr.kernbase = VM_MIN_KERNEL_ADDRESS;
 	mdhdr.dmapbase = DMAP_MIN_ADDRESS;
 	mdhdr.dmapend = DMAP_MAX_ADDRESS;
@@ -267,6 +274,12 @@ minidumpsys(struct dumperinfo *di)
 	printf("Physical memory: %ju MB\n", ptoa((uintmax_t)physmem) / 1048576);
 	printf("Dumping %llu MB:", (long long)dumpsize >> 20);
 
+	/*
+	 * Freeze bitmap of pages to dump, so that disk writing routines don't
+	 * accidentally modify it (while doing memory allocations, etc).
+	 */
+	bitmap_frozen = 1;
+
 	/* Dump leader */
 	error = dump_write(di, &kdh, 0, dumplo, sizeof(kdh));
 	if (error)
@@ -274,9 +287,9 @@ minidumpsys(struct dumperinfo *di)
 	dumplo += sizeof(kdh);
 
 	/* Dump my header */
-	bzero(&fakept, sizeof(fakept));
-	bcopy(&mdhdr, &fakept, sizeof(mdhdr));
-	error = blk_write(di, (char *)&fakept, 0, PAGE_SIZE);
+	bzero(&fakepd, sizeof(fakepd));
+	bcopy(&mdhdr, &fakepd, sizeof(mdhdr));
+	error = blk_write(di, (char *)&fakepd, 0, PAGE_SIZE);
 	if (error)
 		goto fail;
 
@@ -290,55 +303,31 @@ minidumpsys(struct dumperinfo *di)
 	if (error)
 		goto fail;
 
-	/* Dump kernel page table pages */
+	/* Dump kernel page directory pages */
+	bzero(fakepd, sizeof(fakepd));
 	pdp = (uint64_t *)PHYS_TO_DMAP(KPDPphys);
 	for (va = VM_MIN_KERNEL_ADDRESS; va < MAX(KERNBASE + NKPT * NBPDR,
-	    kernel_vm_end); va += NBPDR) {
+	    kernel_vm_end); va += NBPDP) {
 		i = (va >> PDPSHIFT) & ((1ul << NPDPEPGSHIFT) - 1);
 		/* We always write a page, even if it is zero */
 		if ((pdp[i] & PG_V) == 0) {
-			bzero(fakept, sizeof(fakept));
-			error = blk_write(di, (char *)&fakept, 0, PAGE_SIZE);
+			error = blk_write(di, (char *)&fakepd, 0, PAGE_SIZE);
 			if (error)
 				goto fail;
-			/* flush, in case we reuse fakept in the same block */
+			/* flush, in case we reuse fakepd in the same block */
 			error = blk_flush(di);
 			if (error)
 				goto fail;
 			continue;
 		}
+
 		pd = (uint64_t *)PHYS_TO_DMAP(pdp[i] & PG_FRAME);
-		j = ((va >> PDRSHIFT) & ((1ul << NPDEPGSHIFT) - 1));
-		if ((pd[j] & (PG_PS | PG_V)) == (PG_PS | PG_V))  {
-			/* This is a single 2M block. Generate a fake PTP */
-			pa = pd[j] & PG_PS_FRAME;
-			for (k = 0; k < NPTEPG; k++) {
-				fakept[k] = (pa + (k * PAGE_SIZE)) | PG_V | PG_RW | PG_A | PG_M;
-			}
-			error = blk_write(di, (char *)&fakept, 0, PAGE_SIZE);
-			if (error)
-				goto fail;
-			/* flush, in case we reuse fakept in the same block */
-			error = blk_flush(di);
-			if (error)
-				goto fail;
-			continue;
-		}
-		if ((pd[j] & PG_V) == PG_V) {
-			pt = (uint64_t *)PHYS_TO_DMAP(pd[j] & PG_FRAME);
-			error = blk_write(di, (char *)pt, 0, PAGE_SIZE);
-			if (error)
-				goto fail;
-		} else {
-			bzero(fakept, sizeof(fakept));
-			error = blk_write(di, (char *)&fakept, 0, PAGE_SIZE);
-			if (error)
-				goto fail;
-			/* flush, in case we reuse fakept in the same block */
-			error = blk_flush(di);
-			if (error)
-				goto fail;
-		}
+		error = blk_write(di, (char *)pd, 0, PAGE_SIZE);
+		if (error)
+			goto fail;
+		error = blk_flush(di);
+		if (error)
+			goto fail;
 	}
 
 	/* Dump memory chunks */
@@ -387,6 +376,9 @@ dump_add_page(vm_paddr_t pa)
 {
 	int idx, bit;
 
+	if (bitmap_frozen)
+		return;
+
 	pa >>= PAGE_SHIFT;
 	idx = pa >> 6;		/* 2^6 = 64 */
 	bit = pa & 63;
@@ -398,8 +390,12 @@ dump_drop_page(vm_paddr_t pa)
 {
 	int idx, bit;
 
+	if (bitmap_frozen)
+		return;
+
 	pa >>= PAGE_SHIFT;
 	idx = pa >> 6;		/* 2^6 = 64 */
 	bit = pa & 63;
 	atomic_clear_long(&vm_page_dump[idx], 1ul << bit);
 }
+
diff --git a/lib/libkvm/kvm_minidump_amd64.c b/lib/libkvm/kvm_minidump_amd64.c
index 8f48f98..88ff0e6 100644
--- a/lib/libkvm/kvm_minidump_amd64.c
+++ b/lib/libkvm/kvm_minidump_amd64.c
@@ -67,7 +67,7 @@ struct vmstate {
 	struct minidumphdr hdr;
 	void *hpt_head[HPT_SIZE];
 	uint64_t *bitmap;
-	uint64_t *ptemap;
+	uint64_t *pdemap;
 };
 
 static void
@@ -127,8 +127,8 @@ _kvm_minidump_freevtop(kvm_t *kd)
 
 	if (vm->bitmap)
 		free(vm->bitmap);
-	if (vm->ptemap)
-		free(vm->ptemap);
+	if (vm->pdemap)
+		free(vm->pdemap);
 	free(vm);
 	kd->vmst = NULL;
 }
@@ -177,17 +177,17 @@ _kvm_minidump_initvtop(kvm_t *kd)
 	}
 	off += round_page(vmst->hdr.bitmapsize);
 
-	vmst->ptemap = _kvm_malloc(kd, vmst->hdr.ptesize);
-	if (vmst->ptemap == NULL) {
-		_kvm_err(kd, kd->program, "cannot allocate %d bytes for ptemap", vmst->hdr.ptesize);
+	vmst->pdemap = _kvm_malloc(kd, vmst->hdr.pdesize);
+	if (vmst->pdemap == NULL) {
+		_kvm_err(kd, kd->program, "cannot allocate %d bytes for pdemap", vmst->hdr.pdesize);
 		return (-1);
 	}
-	if (pread(kd->pmfd, vmst->ptemap, vmst->hdr.ptesize, off) !=
-	    vmst->hdr.ptesize) {
-		_kvm_err(kd, kd->program, "cannot read %d bytes for ptemap", vmst->hdr.ptesize);
+	if (pread(kd->pmfd, vmst->pdemap, vmst->hdr.pdesize, off) !=
+	    vmst->hdr.pdesize) {
+		_kvm_err(kd, kd->program, "cannot read %d bytes for pdemap", vmst->hdr.pdesize);
 		return (-1);
 	}
-	off += vmst->hdr.ptesize;
+	off += vmst->hdr.pdesize;
 
 	/* build physical address hash table for sparse pages */
 	inithash(kd, vmst->bitmap, vmst->hdr.bitmapsize, off);
@@ -198,25 +198,49 @@ _kvm_minidump_initvtop(kvm_t *kd)
 static int
 _kvm_minidump_vatop(kvm_t *kd, u_long va, off_t *pa)
 {
+	pt_entry_t pt[NPTEPG];
 	struct vmstate *vm;
 	u_long offset;
-	pt_entry_t pte;
+	pd_entry_t pde;
+	pd_entry_t pte;
 	u_long pteindex;
+	u_long pdeindex;
 	int i;
 	u_long a;
 	off_t ofs;
 
 	vm = kd->vmst;
-	offset = va & (PAGE_SIZE - 1);
+	offset = va & PAGE_MASK;
 
 	if (va >= vm->hdr.kernbase) {
-		pteindex = (va - vm->hdr.kernbase) >> PAGE_SHIFT;
-		pte = vm->ptemap[pteindex];
-		if (((u_long)pte & PG_V) == 0) {
-			_kvm_err(kd, kd->program, "_kvm_vatop: pte not valid");
+		pdeindex = (va - vm->hdr.kernbase) >> PDRSHIFT;
+		pde = vm->pdemap[pdeindex];
+		if (((u_long)pde & PG_V) == 0) {
+			_kvm_err(kd, kd->program, "_kvm_vatop: pde not valid");
 			goto invalid;
 		}
-		a = pte & PG_FRAME;
+		if ((pde & PG_PS) == 0) {
+			a = pde & PG_FRAME;
+			ofs = hpt_find(kd, a);
+			if (ofs == -1) {
+				_kvm_err(kd, kd->program, "_kvm_vatop: pt physical address 0x%lx not in minidump", a);
+				goto invalid;
+			}
+			if (pread(kd->pmfd, &pt, PAGE_SIZE, ofs) != PAGE_SIZE) {
+				_kvm_err(kd, kd->program, "cannot read %d bytes for pt", PAGE_SIZE);
+				return (-1);
+			}
+			pteindex = (va >> PAGE_SHIFT) & ((1ul << NPTEPGSHIFT) - 1);
+			pte = pt[pteindex];
+			if (((u_long)pte & PG_V) == 0) {
+				_kvm_err(kd, kd->program, "_kvm_vatop: pte not valid");
+				goto invalid;
+			}
+			a = pte & PG_FRAME;
+		} else {
+			a = pde & PG_PS_FRAME;
+			a += (va & PDRMASK) ^ offset;
+		}
 		ofs = hpt_find(kd, a);
 		if (ofs == -1) {
 			_kvm_err(kd, kd->program, "_kvm_vatop: physical address 0x%lx not in minidump", a);