diff --git a/src/addrxlat/x86_64.c b/src/addrxlat/x86_64.c
index 4aa460ca..2e11fe9b 100644
--- a/src/addrxlat/x86_64.c
+++ b/src/addrxlat/x86_64.c
@@ -541,9 +541,10 @@ linux_ktext_extents(struct os_init_data *ctl,
 
 	linearoff = ctl->sys->meth[ADDRXLAT_SYS_METH_KTEXT].param.linear.off;
 	*high = *low;
-	status = highest_linear(&step, high, LINUX_KTEXT_END_NOKASLR,
-				linearoff);
-	if (status == ADDRXLAT_OK && *high == LINUX_KTEXT_END_NOKASLR) {
+	if (*high <= LINUX_KTEXT_END_NOKASLR)
+		status = highest_linear(&step, high, LINUX_KTEXT_END_NOKASLR,
+					linearoff);
+	if (status == ADDRXLAT_OK && *high >= LINUX_KTEXT_END_NOKASLR) {
 		++*high;
 		status = highest_linear(&step, high, LINUX_KTEXT_END,
 					linearoff);
diff --git a/src/kdumpfile/util.c b/src/kdumpfile/util.c
index d9648c15..23d698e8 100644
--- a/src/kdumpfile/util.c
+++ b/src/kdumpfile/util.c
@@ -1345,7 +1345,7 @@ read_blob_attr(kdump_ctx_t *ctx, unsigned fidx, off_t off, size_t size,
 	struct fcache_chunk fch;
 	kdump_status ret;
 
-	ret = fcache_get_chunk(ctx->shared->fcache, &fch, size, fidx, off);
+	ret = flatmap_get_chunk(ctx->shared->flatmap, &fch, size, fidx, off);
 	if (ret != KDUMP_OK)
 		return set_error(ctx, ret,
 				 "Cannot read %s (%zu bytes at %llu in %s)",
diff --git a/tests/Makefile.am b/tests/Makefile.am
index 6b7697fe..e751cebf 100644
--- a/tests/Makefile.am
+++ b/tests/Makefile.am
@@ -196,7 +196,9 @@ test_scripts = \
 	diskdump-empty-s390x \
 	diskdump-empty-x86_64 \
 	diskdump-basic-raw \
+	diskdump-basic-vmcoreinfo \
 	diskdump-flat-raw \
+	diskdump-flat-vmcoreinfo \
 	diskdump-multiread \
 	diskdump-excluded \
 	diskdump-split \
@@ -295,6 +297,7 @@ test_scripts = \
 	xlat-linux-x86_64-ktext-40M \
 	xlat-linux-x86_64-ktext-512M \
 	xlat-linux-x86_64-ktext-520M \
+	xlat-linux-x86_64-ktext-54M-kaslr \
 	xlat-linux-x86_64-old \
 	xlat-linux-x86_64-old-nover \
 	xlat-linux-x86_64-2.6.11 \
@@ -392,6 +395,7 @@ dist_check_DATA = \
 	diskdump-split.expect.3 \
 	sys-xlat-x86_64-linux.expect \
 	sys-xlat-x86_64-linux-xen.expect \
+	vmcoreinfo.data \
 	xlatmap.expect \
 	xlat-os-aarch64-none.expect \
 	xlat-os-ia32-none.expect \
@@ -476,6 +480,9 @@ dist_check_DATA = \
 	xlat-linux-x86_64-ktext-520M.data \
 	xlat-linux-x86_64-ktext-520M.expect \
 	xlat-linux-x86_64-ktext-520M.sym \
+	xlat-linux-x86_64-ktext-54M-kaslr.data \
+	xlat-linux-x86_64-ktext-54M-kaslr.expect \
+	xlat-linux-x86_64-ktext-54M-kaslr.sym \
 	xlat-linux-x86_64-old.expect \
 	xlat-linux-x86_64-old-nover.data \
 	xlat-linux-x86_64-old-nover.expect \
diff --git a/tests/diskdump-basic b/tests/diskdump-basic
index 1f676a05..831cc93f 100644
--- a/tests/diskdump-basic
+++ b/tests/diskdump-basic
@@ -14,7 +14,6 @@ echo "@0 $pageflags" > "$datafile"
 cat "$expectfile" >> "$datafile"
 
 ./mkdiskdump "$dumpfile" <<EOF
-$extraparam
 version = 6
 arch_name = x86_64
 block_size = 4096
@@ -32,6 +31,7 @@ uts.domainname = (none)
 nr_cpus = 1
 
 DATA = $datafile
+$extraparam
 EOF
 rc=$?
 if [ $rc -ne 0 ]; then
@@ -43,6 +43,7 @@ echo "Created DISKDUMP dump: $dumpfile"
 ./checkattr "$dumpfile" <<EOF
 file.pagemap = bitmap: 1
 memory.pagemap = bitmap: 1
+$extracheckattr
 EOF
 rc=$?
 if [ $rc -ne 0 ]; then
diff --git a/tests/diskdump-basic-vmcoreinfo b/tests/diskdump-basic-vmcoreinfo
new file mode 100755
index 00000000..2e43e635
--- /dev/null
+++ b/tests/diskdump-basic-vmcoreinfo
@@ -0,0 +1,20 @@
+#! /bin/sh
+
+#
+# Create a diskdump file with VMCOREINFO data. The corresponding header field
+# was added in v3 and superseded by ELF notes in v4, so the version is forced
+# to v3 here.
+#
+
+pageflags=raw
+extraparam="
+version = 3
+VMCOREINFO = vmcoreinfo.data
+"
+extracheckattr="
+linux.vmcoreinfo.lines.OSRELEASE = string:6.4.3-1-default
+linux.vmcoreinfo.lines.PAGESIZE = string:4096
+linux.vmcoreinfo.lines.CRASHTIME = string:1689103980
+"
+. "$srcdir"/diskdump-basic
+exit 0
diff --git a/tests/diskdump-flat-vmcoreinfo b/tests/diskdump-flat-vmcoreinfo
new file mode 100755
index 00000000..a85bf3b1
--- /dev/null
+++ b/tests/diskdump-flat-vmcoreinfo
@@ -0,0 +1,20 @@
+#! /bin/sh
+
+#
+# Create a flattened diskdump file with VMCOREINFO data.
+# See also diskdump-basic-vmcoreinfo.
+#
+
+pageflags=raw
+extraparam="
+flattened = yes
+version = 3
+VMCOREINFO = vmcoreinfo.data
+"
+extracheckattr="
+linux.vmcoreinfo.lines.OSRELEASE = string:6.4.3-1-default
+linux.vmcoreinfo.lines.PAGESIZE = string:4096
+linux.vmcoreinfo.lines.CRASHTIME = string:1689103980
+"
+. "$srcdir"/diskdump-basic
+exit 0
diff --git a/tests/mkdiskdump.c b/tests/mkdiskdump.c
index 98ebc8f4..de023d33 100644
--- a/tests/mkdiskdump.c
+++ b/tests/mkdiskdump.c
@@ -85,11 +85,6 @@ enum compress_method {
 	COMPRESS_ZSTD,
 };
 
-struct data_block {
-	off_t filepos;
-	struct blob *blob;
-};
-
 static bool flattened;
 static unsigned long long flattened_type = MDF_TYPE_FLAT_HEADER;
 static unsigned long long flattened_version = MDF_VERSION_FLAT_HEADER;
@@ -123,9 +118,9 @@ static unsigned long long split;
 static unsigned long long start_pfn;
 static unsigned long long end_pfn;
 
-static struct data_block vmcoreinfo;
-static struct data_block notes;
-static struct data_block eraseinfo;
+static struct blob *vmcoreinfo;
+static struct blob *notes;
+static struct blob *eraseinfo;
 
 static char *vmcoreinfo_file;
 static char *note_file;
@@ -251,6 +246,7 @@ writeheader_32(FILE *f)
 	struct timeval tv;
 	struct disk_dump_header_32 hdr;
 	struct kdump_sub_header_32 subhdr;
+	off_t pos;
 
 	if (gettimeofday(&tv, NULL) != 0) {
 		perror("gettimeofday");
@@ -290,23 +286,45 @@ writeheader_32(FILE *f)
 	if (write_chunk(f, 0, &hdr, sizeof hdr, "header"))
 		return TEST_ERR;
 
+	pos = DISKDUMP_HEADER_BLOCKS * block_size + sizeof(subhdr);
 	subhdr.phys_base = htodump32(be, phys_base);
 	subhdr.dump_level = htodump32(be, dump_level);
 	subhdr.split = htodump32(be, split);
 	subhdr.start_pfn = htodump32(be, start_pfn);
 	subhdr.end_pfn = htodump32(be, end_pfn);
-	subhdr.offset_vmcoreinfo = htodump64(be, vmcoreinfo.filepos);
-	subhdr.size_vmcoreinfo = htodump32(be, (vmcoreinfo.blob
-						? vmcoreinfo.blob->length
-						: 0));
-	subhdr.offset_note = htodump64(be, notes.filepos);
-	subhdr.size_note = htodump32(be, (notes.blob
-					  ? notes.blob->length
-					  : 0));
-	subhdr.offset_eraseinfo = htodump64(be, eraseinfo.filepos);
-	subhdr.size_eraseinfo = htodump32(be, (eraseinfo.blob
-					       ? eraseinfo.blob->length
-					       : 0));
+	if (vmcoreinfo) {
+		subhdr.offset_vmcoreinfo = htodump64(be, pos);
+		subhdr.size_vmcoreinfo = htodump32(be, vmcoreinfo->length);
+		if (write_chunk(f, pos, vmcoreinfo->data, vmcoreinfo->length,
+				"VMCOREINFO"))
+			return TEST_ERR;
+		pos += vmcoreinfo->length;
+	} else {
+		subhdr.offset_vmcoreinfo = htodump64(be, 0);
+		subhdr.size_vmcoreinfo = htodump32(be, 0);
+	}
+	if (notes) {
+		subhdr.offset_note = htodump64(be, pos);
+		subhdr.size_note = htodump32(be, notes->length);
+		if (write_chunk(f, pos, notes->data, notes->length,
+				"ELF notes"))
+			return TEST_ERR;
+		pos += notes->length;
+	} else {
+		subhdr.offset_note = htodump64(be, 0);
+		subhdr.size_note = htodump32(be, 0);
+	}
+	if (eraseinfo) {
+		subhdr.offset_eraseinfo = htodump64(be, pos);
+		subhdr.size_eraseinfo = htodump32(be, eraseinfo->length);
+		if (write_chunk(f, pos, notes->data, notes->length,
+				"eraseinfo"))
+			return TEST_ERR;
+		pos += eraseinfo->length;
+	} else {
+		subhdr.offset_eraseinfo = htodump64(be, 0);
+		subhdr.size_eraseinfo = htodump32(be, 0);
+	}
 	subhdr.start_pfn_64 = htodump64(be, start_pfn);
 	subhdr.end_pfn_64 = htodump64(be, end_pfn);
 	subhdr.max_mapnr_64 = htodump64(be, max_mapnr);
@@ -324,6 +342,7 @@ writeheader_64(FILE *f)
 	struct timeval tv;
 	struct disk_dump_header_64 hdr;
 	struct kdump_sub_header_64 subhdr;
+	off_t pos;
 
 	if (gettimeofday(&tv, NULL) != 0) {
 		perror("gettimeofday");
@@ -363,23 +382,45 @@ writeheader_64(FILE *f)
 	if (write_chunk(f, 0, &hdr, sizeof hdr, "header"))
 		return TEST_ERR;
 
+	pos = DISKDUMP_HEADER_BLOCKS * block_size + sizeof(subhdr);
 	subhdr.phys_base = htodump64(be, phys_base);
 	subhdr.dump_level = htodump32(be, dump_level);
 	subhdr.split = htodump32(be, split);
 	subhdr.start_pfn = htodump64(be, start_pfn);
 	subhdr.end_pfn = htodump64(be, end_pfn);
-	subhdr.offset_vmcoreinfo = htodump64(be, vmcoreinfo.filepos);
-	subhdr.size_vmcoreinfo = htodump64(be, (vmcoreinfo.blob
-						? vmcoreinfo.blob->length
-						: 0));
-	subhdr.offset_note = htodump64(be, notes.filepos);
-	subhdr.size_note = htodump64(be, (notes.blob
-					  ? notes.blob->length
-					  : 0));
-	subhdr.offset_eraseinfo = htodump64(be, eraseinfo.filepos);
-	subhdr.size_eraseinfo = htodump64(be, (eraseinfo.blob
-					       ? eraseinfo.blob->length
-					       : 0));
+	if (vmcoreinfo) {
+		subhdr.offset_vmcoreinfo = htodump64(be, pos);
+		subhdr.size_vmcoreinfo = htodump64(be, vmcoreinfo->length);
+		if (write_chunk(f, pos, vmcoreinfo->data, vmcoreinfo->length,
+				"VMCOREINFO"))
+			return TEST_ERR;
+		pos += vmcoreinfo->length;
+	} else {
+		subhdr.offset_vmcoreinfo = htodump64(be, 0);
+		subhdr.size_vmcoreinfo = htodump64(be, 0);
+	}
+	if (notes) {
+		subhdr.offset_note = htodump64(be, pos);
+		subhdr.size_note = htodump64(be, notes->length);
+		if (write_chunk(f, pos, notes->data, notes->length,
+				"ELF notes"))
+			return TEST_ERR;
+		pos += notes->length;
+	} else {
+		subhdr.offset_note = htodump64(be, 0);
+		subhdr.size_note = htodump64(be, 0);
+	}
+	if (eraseinfo) {
+		subhdr.offset_eraseinfo = htodump64(be, pos);
+		subhdr.size_eraseinfo = htodump64(be, eraseinfo->length);
+		if (write_chunk(f, pos, notes->data, notes->length,
+				"eraseinfo"))
+			return TEST_ERR;
+		pos += eraseinfo->length;
+	} else {
+		subhdr.offset_eraseinfo = htodump64(be, 0);
+		subhdr.size_eraseinfo = htodump64(be, 0);
+	}
 	subhdr.start_pfn_64 = htodump64(be, start_pfn);
 	subhdr.end_pfn_64 = htodump64(be, end_pfn);
 	subhdr.max_mapnr_64 = htodump64(be, max_mapnr);
@@ -904,20 +945,20 @@ main(int argc, char **argv)
 		return rc;
 
 	if (vmcoreinfo_file) {
-		vmcoreinfo.blob = slurp(vmcoreinfo_file);
-		if (vmcoreinfo.blob == NULL)
+		vmcoreinfo = slurp(vmcoreinfo_file);
+		if (vmcoreinfo == NULL)
 			return TEST_ERR;
 	}
 
 	if (note_file) {
-		notes.blob = slurp(note_file);
-		if (notes.blob == NULL)
+		notes = slurp(note_file);
+		if (notes == NULL)
 			return TEST_ERR;
 	}
 
 	if (eraseinfo_file) {
-		eraseinfo.blob = slurp(eraseinfo_file);
-		if (eraseinfo.blob == NULL)
+		eraseinfo = slurp(eraseinfo_file);
+		if (eraseinfo == NULL)
 			return TEST_ERR;
 	}
 
diff --git a/tests/vmcoreinfo.data b/tests/vmcoreinfo.data
new file mode 100644
index 00000000..986b6bc0
--- /dev/null
+++ b/tests/vmcoreinfo.data
@@ -0,0 +1,3 @@
+OSRELEASE=6.4.3-1-default
+PAGESIZE=4096
+CRASHTIME=1689103980
diff --git a/tests/xlat-linux-x86_64-ktext-54M-kaslr b/tests/xlat-linux-x86_64-ktext-54M-kaslr
new file mode 100755
index 00000000..7d1596e1
--- /dev/null
+++ b/tests/xlat-linux-x86_64-ktext-54M-kaslr
@@ -0,0 +1,14 @@
+#! /bin/bash
+
+#
+# Check Linux X86_64 translation with a 54M kASLR ktext mapping starting
+# above the fixed (non-kASLR) virtual address region.
+#
+
+opts=(
+    arch=x86_64
+    ostype=linux
+    phys_base=0x23c00000
+)
+
+. "$srcdir"/xlat-os-common
diff --git a/tests/xlat-linux-x86_64-ktext-54M-kaslr.data b/tests/xlat-linux-x86_64-ktext-54M-kaslr.data
new file mode 100644
index 00000000..2c77ff61
--- /dev/null
+++ b/tests/xlat-linux-x86_64-ktext-54M-kaslr.data
@@ -0,0 +1,9 @@
+# kernel text
+@0x4c610ff8
+000000004c615067
+@0x4c615ff0
+000000004c616063
+@0x4c616000
+0000000000000000*313
+000000004ae001e1*27+200000
+0000000000000000*172
diff --git a/tests/xlat-linux-x86_64-ktext-54M-kaslr.expect b/tests/xlat-linux-x86_64-ktext-54M-kaslr.expect
new file mode 100644
index 00000000..b03a342f
--- /dev/null
+++ b/tests/xlat-linux-x86_64-ktext-54M-kaslr.expect
@@ -0,0 +1,40 @@
+@rootpgt: PGT
+  target_as=MACHPHYSADDR
+  root=KVADDR:0xffffffffa8a10000
+  pte_mask=0x0
+  pte_format=x86_64
+  fields=12,9,9,9,9
+
+@ktext: LINEAR
+  target_as=KPHYSADDR
+  off=0xa3c00000
+
+@machphys_kphys: LINEAR
+  target_as=KPHYSADDR
+  off=0x0
+
+@kphys_machphys: LINEAR
+  target_as=MACHPHYSADDR
+  off=0x0
+
+KV -> HW:
+0-7fffffffffff: @rootpgt
+800000000000-ffff7fffffffffff: NONE
+ffff800000000000-ffffffffffffffff: @rootpgt
+
+KV -> PHYS:
+0-7fffffffffff: @rootpgt
+800000000000-ffff7fffffffffff: NONE
+ffff800000000000-ffffffffa71fffff: @rootpgt
+ffffffffa7200000-ffffffffaa7fffff: @ktext
+ffffffffaa800000-ffffffffffffffff: @rootpgt
+
+KPHYS -> DIRECT:
+
+MACHPHYS -> KPHYS:
+0-fffffffffffff: @machphys_kphys
+10000000000000-ffffffffffffffff: NONE
+
+KPHYS -> MACHPHYS:
+0-fffffffffffff: @kphys_machphys
+10000000000000-ffffffffffffffff: NONE
diff --git a/tests/xlat-linux-x86_64-ktext-54M-kaslr.sym b/tests/xlat-linux-x86_64-ktext-54M-kaslr.sym
new file mode 100644
index 00000000..3abd9936
--- /dev/null
+++ b/tests/xlat-linux-x86_64-ktext-54M-kaslr.sym
@@ -0,0 +1,4 @@
+@VALUE(init_top_pgt)
+ffffffffa8a10000
+@VALUE(_stext)
+ffffffffa7200000