diff --git a/disktools.py b/disktools.py
index 4bc0fa7c..39f2c042 100644
--- a/disktools.py
+++ b/disktools.py
@@ -1117,6 +1117,7 @@ def probePartitioningScheme(device):
     if out == 'dos':
         partitionType = constants.PARTITION_DOS
 
+    logger.debug("probePartitioningScheme(%r) => %r", device, partitionType)
     return partitionType
 
 def PartitionTool(device, partitionType=None):
diff --git a/diskutil.py b/diskutil.py
index bbfa2d65..575bdc7b 100644
--- a/diskutil.py
+++ b/diskutil.py
@@ -493,6 +493,8 @@ def __init__(self, device):
         self.storage = (None, None)
         self.logs = (False, None)
         self.swap = (False, None)
+    def __str__(self):
+        return "Disk({})".format(self.__dict__)
 
 INSTALL_RETAIL = 1
 STORAGE_LVM = 1
@@ -512,10 +514,12 @@ def probeDisk(device):
         swap is a tuple of True or False and the partition device
     """
 
+    logger.debug("probeDisk(%r)", device)
     disk = Disk(device)
     possible_srs = []
 
     tool = PartitionTool(device)
+    tool.dump()
     for num, part in tool.items():
         label = None
         part_device = tool._partitionDevice(num)
@@ -543,6 +547,8 @@ def probeDisk(device):
             disk.swap = (True, part_device)
         elif part['id'] == GPTPartitionTool.ID_EFI_BOOT or part['id'] == GPTPartitionTool.ID_BIOS_BOOT:
             disk.boot = (True, part_device)
+        else:
+            logger.info("part %s has unknown id: %s", num, part)
 
     lv_tool = len(possible_srs) and LVMTool()
     for num in possible_srs:
diff --git a/restore.py b/restore.py
index 3da45cc9..962a13df 100644
--- a/restore.py
+++ b/restore.py
@@ -40,6 +40,8 @@ def restoreFromBackup(backup, progress=lambda x: ()):
     assert disk_device.startswith('/dev/')
 
     restore_partition = disk.root[1]
+    if not isinstance(restore_partition, str):
+        raise RuntimeError("failed to identify root partition to restore to, disk=%s" % disk)
     logger.log("Restoring to partition %s." % restore_partition)
 
     boot_part = tool.getPartition(boot_partnum)
@@ -138,6 +140,7 @@ def restore_partitions():
         try:
             util.mkfs(constants.rootfs_type, restore_partition)
         except Exception as e:
+            logger.critical("Failed to create root filesystem", exc_info=1)
             raise RuntimeError("Failed to create root filesystem: %s" % e)
 
         if efi_boot: