diff --git a/include/ntux/ntux.h b/include/ntux/ntux.h
index 3e9782e..817b5c8 100644
--- a/include/ntux/ntux.h
+++ b/include/ntux/ntux.h
@@ -54,6 +54,7 @@ enum ntux_custom_error {
 	NTUX_ERR_FLOW_ERROR,
 	NTUX_ERR_FLEE_ERROR,
 	NTUX_ERR_LDSO_INIT,
+	NTUX_ERR_NOT_IMPLEMENTED,
 };
 
 enum ntux_cmd {
diff --git a/src/cmds/ntux_cmd_chmod.c b/src/cmds/ntux_cmd_chmod.c
index 416d756..b90acfe 100644
--- a/src/cmds/ntux_cmd_chmod.c
+++ b/src/cmds/ntux_cmd_chmod.c
@@ -14,6 +14,7 @@
 #include <psxxfi/xfi_ofd.h>
 #include <psxxfi/xfi_unicode.h>
 
+#include <ntapi/nt_object.h>
 #include <ntapi/nt_acl.h>
 #include <ntapi/nt_file.h>
 
@@ -22,6 +23,12 @@
 #include "ntux_nolibc_impl.h"
 #include "ntux_errinfo_impl.h"
 
+#define __SID_SYSTEM			{1,1,{{0,0,0,0,0,5}},{18}}
+#define __SID_ADMINISTRATORS		{1,2,{{0,0,0,0,0,5}},{32,544}}
+
+static const nt_sid    sid_system       = __SID_SYSTEM;
+static const nt_sid_os sid_admins       = __SID_ADMINISTRATORS;
+
 static int ntux_cmd_chmod_ret(int fd, struct __ofd * ofd, void * hasync, int ret)
 {
 	if (hasync)
@@ -36,6 +43,18 @@ static int ntux_cmd_chmod_ret(int fd, struct __ofd * ofd, void * hasync, int ret
 	return ret;
 }
 
+static nt_sid * ntux_cmd_chmod_sid_from_name(const char * name)
+{
+	if (!strcmp(name,"Administrators"))
+		return (nt_sid *)&sid_admins;
+
+	else if (!strcmp(name,"SYSTEM"))
+		return (nt_sid *)&sid_system;
+
+	else
+		return 0;
+}
+
 int ntux_cmd_chmod(const struct ntux_driver_ctx * dctx, const char * dunit)
 {
 	intptr_t		ret;
@@ -46,11 +65,14 @@ int ntux_cmd_chmod(const struct ntux_driver_ctx * dctx, const char * dunit)
 	nt_sd *			srcsd;
 	nt_sd_common_buffer	dstsd;
 	nt_sd_common_meta	meta;
+	nt_sid *		owner;
+	nt_sid *		group;
 	uint32_t		access_owner;
 	uint32_t		access_group;
 	uint32_t		access_other;
 	uint32_t		access_admin;
 	uint32_t		ace_flags;
+	uint32_t		sec_mask;
 	size_t			size;
 	int			fd      = -1;
 	struct __ofd *		ofd     = 0;
@@ -74,6 +96,26 @@ int ntux_cmd_chmod(const struct ntux_driver_ctx * dctx, const char * dunit)
 				dctx,
 				NTUX_ERR_FLEE_ERROR));
 
+	/* initial --owner and --group support: Administrators, SYSTEM */
+	owner = 0;
+	group = 0;
+
+	if (dctx->cctx->owner)
+		if (!(owner = ntux_cmd_chmod_sid_from_name(dctx->cctx->owner)))
+			return ntux_cmd_chmod_ret(
+				0,0,0,
+				NTUX_CUSTOM_ERROR(
+					dctx,
+					NTUX_ERR_NOT_IMPLEMENTED));
+
+	if (dctx->cctx->group)
+		if (!(group = ntux_cmd_chmod_sid_from_name(dctx->cctx->group)))
+			return ntux_cmd_chmod_ret(
+				0,0,0,
+				NTUX_CUSTOM_ERROR(
+					dctx,
+					NTUX_ERR_NOT_IMPLEMENTED));
+
 	/* init */
 	ntux_driver_set_ectx(
 		dctx,0,dunit);
@@ -102,11 +144,14 @@ int ntux_cmd_chmod(const struct ntux_driver_ctx * dctx, const char * dunit)
 				NTUX_ERR_FLOW_ERROR));
 
 	/* hasync */
+	sec_mask  = NT_SEC_READ_CONTROL;
+	sec_mask |= NT_SEC_WRITE_DAC;
+	sec_mask |= owner ? NT_SEC_WRITE_OWNER : 0;
+
 	if ((status = __xfi_fs_open_async(
 			&hasync,
 			ofd->info.hfile,0,
-			NT_SEC_READ_CONTROL
-				| NT_SEC_WRITE_DAC,
+			sec_mask,
 			NT_FILE_SHARE_READ
 				| NT_FILE_SHARE_WRITE
 				| NT_FILE_SHARE_DELETE)))
@@ -151,15 +196,18 @@ int ntux_cmd_chmod(const struct ntux_driver_ctx * dctx, const char * dunit)
 	/* updated dacl */
 	__xfi_acl_init_common_descriptor(
 		&dstsd,
-		meta.owner,meta.group,0,0,
+		owner ? owner : meta.owner,
+		group ? group : meta.group,
+		0,0,
 		access_owner,access_group,access_other,
 		access_admin,meta.system_acc,
 		ace_flags);
 
+	sec_mask  = NT_DACL_SECURITY_INFORMATION;
+	sec_mask |= owner ? NT_OWNER_SECURITY_INFORMATION : 0;
+
 	if ((status = __xfi_set_security_object(
-			hasync,
-			NT_DACL_SECURITY_INFORMATION,
-			&dstsd.sd)))
+			hasync,sec_mask,&dstsd.sd)))
 		return ntux_cmd_chmod_ret(
 			fd,ofd,hasync,
 			NTUX_SYSTEM_ERROR(dctx));
diff --git a/src/output/ntux_output_error.c b/src/output/ntux_output_error.c
index b500eb5..be58ba1 100644
--- a/src/output/ntux_output_error.c
+++ b/src/output/ntux_output_error.c
@@ -58,7 +58,10 @@ static const char * ntux_output_strerror(
 		return ictx->errsbuf;
 	}
 
-	if (erri->eflags & NTUX_ERROR_CUSTOM)
+	if ((erri->eflags & NTUX_ERROR_CUSTOM) && (erri->elibcode == NTUX_ERR_NOT_IMPLEMENTED))
+		return "status: support for one or more option values is not yet implemented";
+
+	else if (erri->eflags & NTUX_ERROR_CUSTOM)
 		return "flow error: unexpected condition or other";
 
 	else if (erri->eflags & NTUX_ERROR_NESTED)