diff --git a/usr.bin/elfctl/elfctl.1 b/usr.bin/elfctl/elfctl.1
--- a/usr.bin/elfctl/elfctl.1
+++ b/usr.bin/elfctl/elfctl.1
@@ -26,7 +26,7 @@
 .\"
 .\" $FreeBSD$
 .\"
-.Dd March 1, 2020
+.Dd January 12, 2021
 .Dt ELFCTL 1
 .Os
 .Sh NAME
@@ -35,6 +35,7 @@
 .Sh SYNOPSIS
 .Nm
 .Op Fl h | Fl -help
+.Op Fl i
 .Op Fl l
 .Op Fl e Ar featurelist
 .Ar
@@ -47,6 +48,9 @@
 .Bl -tag -width indent
 .It Fl h | Fl -help
 Print a usage message and exit.
+.It Fl i
+Ignore unknown feature flags in
+.Ar featurelist .
 .It Fl l
 List known ELF feature flags.
 .It Fl e Ar featurelist
diff --git a/usr.bin/elfctl/elfctl.c b/usr.bin/elfctl/elfctl.c
--- a/usr.bin/elfctl/elfctl.c
+++ b/usr.bin/elfctl/elfctl.c
@@ -81,7 +81,9 @@
 #else
 #define SUPPORTED_ENDIAN ELFDATA2MSB
 #endif
-		
+
+static bool iflag;
+
 int
 main(int argc, char **argv)
 {
@@ -100,8 +102,11 @@
 	if (elf_version(EV_CURRENT) == EV_NONE)
 		errx(EXIT_FAILURE, "elf_version error");
 
-	while ((ch = getopt_long(argc, argv, "hle:", long_opts, NULL)) != -1) {
+	while ((ch = getopt_long(argc, argv, "hile:", long_opts, NULL)) != -1) {
 		switch (ch) {
+		case 'i':
+			iflag = true;
+			break;
 		case 'l':
 			print_features();
 			lflag = true;
@@ -197,6 +202,7 @@
   Set or display the control features for an ELF object.\n\n\
   Supported options are:\n\
   -l                        List known control features.\n\
+  -i                        Ignore unknown features.\n\
   -e [+-=]feature,list      Edit features from a comma separated list.\n\
   -h | --help               Print a usage message and exit.\n"
 
@@ -229,7 +235,8 @@
 		}
 		if (i == len) {
 			warnx("%s is not a valid feature", feature);
-			return (false);
+			if (!iflag)
+				return (false);
 		}
 	}