diff --git a/lib/opcodes.py b/lib/opcodes.py
index 32ffc8885ea180c412b60539a1bf32bfabf14d88..d8ab17ca08ce4c64f8d5a118be3eb5e8df478a63 100644
--- a/lib/opcodes.py
+++ b/lib/opcodes.py
@@ -988,7 +988,7 @@ class OpOobCommand(OpCode):
   OP_PARAMS = [
     ("node_names", ht.EmptyList, ht.TListOf(ht.TNonEmptyString),
      "List of nodes to run the OOB command against"),
-    ("command", None, ht.TElemOf(constants.OOB_COMMANDS),
+    ("command", ht.NoDefault, ht.TElemOf(constants.OOB_COMMANDS),
      "OOB command to be run"),
     ("timeout", constants.OOB_TIMEOUT, ht.TInt,
      "Timeout before the OOB helper will be terminated"),
diff --git a/man/gnt-instance.rst b/man/gnt-instance.rst
index 3cb2cecdaeb82ddbde565252ac08d8149a590937..db858cd6570c3669b989604f17da98a219daddf7 100644
--- a/man/gnt-instance.rst
+++ b/man/gnt-instance.rst
@@ -923,8 +923,8 @@ MODIFY
 | [{-H|\--hypervisor-parameters} *HYPERVISOR\_PARAMETERS*]
 | [{-B|\--backend-parameters} *BACKEND\_PARAMETERS*]
 | [{-m|\--runtime-memory} *SIZE*]
-| [\--net add*[:options]* \| \--net remove \| \--net *N:options*]
-| [\--disk add:size=*SIZE*[,vg=*VG*][,metavg=*VG*] \| \--disk remove \|
+| [\--net add*[:options]* \| \--net [*N*:]remove \| \--net *N:options*]
+| [\--disk add:size=*SIZE*[,vg=*VG*][,metavg=*VG*] \| \--disk [*N*:]remove \|
 |  \--disk *N*:mode=*MODE*]
 | [{-t|\--disk-template} plain | {-t|\--disk-template} drbd -n *new_secondary*] [\--no-wait-for-sync]
 | [\--os-type=*OS* [\--force-variant]]
diff --git a/man/gnt-os.rst b/man/gnt-os.rst
index 55fcd6a512d4af3830d23b9278428d1fd93ffc1c..2c81ffbe5cf458522653cd013cfe91d1e88f5b7a 100644
--- a/man/gnt-os.rst
+++ b/man/gnt-os.rst
@@ -62,7 +62,7 @@ list, but is available for installation. The 'blacklisted' state means
 that the OS is not listed and is also not allowed for new instance
 creations (but can be used for reinstalling old instances).
 
-Note: The given operating system doesn't have to exists. This allows
+Note: The given operating system doesn't have to exist. This allows
 preseeding the settings for operating systems not yet known to
 **gnt-os**.