diff --git a/lib/opcodes.py b/lib/opcodes.py
index 17bdc250c472dfb3214fcfbdfd90d9da96836358..5506c7902ff633e94f603413d84e597f8b5c4662 100644
--- a/lib/opcodes.py
+++ b/lib/opcodes.py
@@ -951,7 +951,7 @@ 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 2f9fdb4052f2c6f00e0d567c8a55f334381dbe94..9c7c2a6ffc2fcfd6f21495021b0a5e3602664f10 100644
--- a/man/gnt-instance.rst
+++ b/man/gnt-instance.rst
@@ -896,8 +896,8 @@ 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**.