diff --git a/src/partition_table.toit b/src/partition_table.toit
index 7b28035..d46a217 100644
--- a/src/partition_table.toit
+++ b/src/partition_table.toit
@@ -213,6 +213,9 @@ class PartitionTable:
     //    ota_1,    app,  ota_1,    0x1b0000,  0x1a0000,
     //    nvs,      data, nvs,      0x350000,  0x010000,
     //    programs, 0x40, 0x00,     0x360000,  0x0a0000, encrypted
+    //
+    // Offsets may be missing, in which case they are calculated from the
+    // previous entry.
 
     table := PartitionTable
 
@@ -221,6 +224,7 @@ class PartitionTable:
       trimmed := line.trim
       trimmed != "" and trimmed[0] != '#'
 
+    next-computed-offset/int? := null
     lines.do: | line/string |
       parts := line.split ","
       if parts.size < 5: throw "Malformed CSV line"
@@ -244,14 +248,21 @@ class PartitionTable:
 
       offset-string := parts[3]
       offset/int := ?
-      if offset-string.starts-with "0x": offset = int.parse offset-string[2..] --radix=16
-      else: offset = int.parse offset-string
+      if offset-string == "":
+        if not next-computed-offset: throw "Missing initial offset"
+        offset = next-computed-offset
+      else if offset-string.starts-with "0x": 
+        offset = int.parse offset-string[2..] --radix=16
+      else: 
+        offset = int.parse offset-string
 
       size-string := parts[4]
       size/int := ?
       if size-string.starts-with "0x": size = int.parse size-string[2..] --radix=16
       else: size = int.parse size-string
 
+      next-computed-offset = offset + size
+
       flags/int := 0
       flag-strings := parts.size > 5 ? parts[5].split "+" : []
       flag-strings.filter --in-place: it != ""
diff --git a/tests/cvs-test-partitions-no-offsets.cvs b/tests/cvs-test-partitions-no-offsets.cvs
new file mode 100644
index 0000000..905dc4e
--- /dev/null
+++ b/tests/cvs-test-partitions-no-offsets.cvs
@@ -0,0 +1,27 @@
+# Copyright (C) 2021 Toitware ApS.
+#
+# This library is free software; you can redistribute it and/or
+# modify it under the terms of the GNU Lesser General Public
+# License as published by the Free Software Foundation; version
+# 2.1 only.
+#
+# This library is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+# Lesser General Public License for more details.
+#
+# The license can be found in the file `LICENSE` in the top level
+# directory of this repository.
+
+# Partition Table for Toit.
+
+# Name,   Type, SubType,  Offset,    Size
+# bootloader,,  ,         0x001000,  0x007000
+# partitions,,  ,         0x008000,  0x000c00
+secure,   0x42, 0x00,     0x009000,  0x004000,
+otadata,  data, ota,              ,  0x002000,
+phy_init, data, phy,              ,  0x001000,
+ota_0,    app,  ota_0,            ,  0x1a0000,
+ota_1,    app,  ota_1,            ,  0x1a0000,
+nvs,      data, nvs,              ,  0x010000,
+programs, 0x40, 0x00,             ,  0x0a0000, encrypted
diff --git a/tests/cvs-test.toit b/tests/cvs-test.toit
index c2c7cc2..bc7ce6a 100644
--- a/tests/cvs-test.toit
+++ b/tests/cvs-test.toit
@@ -13,9 +13,13 @@ main:
   program-dir := fs.dirname program-path
   bin-contents := file.read-contents "$program-dir/cvs-test-partitions.bin"
   csv-contents := file.read-contents "$program-dir/cvs-test-partitions.cvs"
+  csv-no-offsets-contents := file.read-contents "$program-dir/cvs-test-partitions-no-offsets.cvs"
 
   partition-table-bin := PartitionTable.decode bin-contents
   partition-table-cvs := PartitionTable.decode csv-contents
+  partition-table-cvs-no-offsets := PartitionTable.decode csv-no-offsets-contents
+
+  expect-equals-partition-tables partition-table-cvs partition-table-cvs-no-offsets
 
   partitions-bin := partition-table-bin.partitions
   partitions-cvs := partition-table-cvs.partitions