diff --git a/helpers/flipbip39_string.c b/helpers/flipbip39_string.c
new file mode 100644
index 00000000000..610acbe2f11
--- /dev/null
+++ b/helpers/flipbip39_string.c
@@ -0,0 +1,78 @@
+/*
+ * Copyright (c) 1988 Regents of the University of California.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. Neither the name of the University nor the names of its contributors
+ *    may be used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+#include "flipbip39_string.h"
+#include <string.h>
+char *
+flipbip39_strtok(char *s, const char *delim)
+{
+	static char *last;
+	return flipbip39_strtok_r(s, delim, &last);
+}
+char *
+flipbip39_strtok_r(char *s, const char *delim, char **last)
+{
+	char *spanp;
+	int c, sc;
+	char *tok;
+	if (s == NULL && (s = *last) == NULL)
+		return (NULL);
+	/*
+	 * Skip (span) leading delimiters (s += strspn(s, delim), sort of).
+	 */
+cont:
+	c = *s++;
+	for (spanp = (char *)delim; (sc = *spanp++) != 0;) {
+		if (c == sc)
+			goto cont;
+	}
+	if (c == 0) {		/* no non-delimiter characters */
+		*last = NULL;
+		return (NULL);
+	}
+	tok = s - 1;
+	/*
+	 * Scan token (scan for delimiters: s += strcspn(s, delim), sort of).
+	 * Note that delim must have one NUL; we stop if we see that, too.
+	 */
+	for (;;) {
+		c = *s++;
+		spanp = (char *)delim;
+		do {
+			if ((sc = *spanp++) == c) {
+				if (c == 0)
+					s = NULL;
+				else
+					s[-1] = 0;
+				*last = s;
+				return (tok);
+			}
+		} while (sc != 0);
+	}
+	/* NOTREACHED */
+}
\ No newline at end of file
diff --git a/helpers/flipbip39_string.h b/helpers/flipbip39_string.h
new file mode 100644
index 00000000000..7eb3aa09263
--- /dev/null
+++ b/helpers/flipbip39_string.h
@@ -0,0 +1,2 @@
+char * flipbip39_strtok(char *s, const char *delim);
+char * flipbip39_strtok_r(char *s, const char *delim, char **last);
diff --git a/views/flipbip39_scene_1.c b/views/flipbip39_scene_1.c
index 19667038d66..f01169c7a11 100644
--- a/views/flipbip39_scene_1.c
+++ b/views/flipbip39_scene_1.c
@@ -7,6 +7,7 @@
 #include "../helpers/flipbip39_haptic.h"
 #include "../helpers/flipbip39_speaker.h"
 #include "../helpers/flipbip39_led.h"
+#include "../helpers/flipbip39_string.h"
 
 #include <string.h>
 // #include "../crypto/bip32.h"
@@ -86,7 +87,7 @@ static void flipbip39_scene_1_model_init(FlipBip39Scene1Model* const model, cons
     }
 
     // Split the mnemonic into parts
-    char *ptr = strtok(str, ",");
+    char *ptr = flipbip39_strtok(str, ",");
     int partnum = 0;
     while(ptr != NULL)
     {
@@ -101,7 +102,7 @@ static void flipbip39_scene_1_model_init(FlipBip39Scene1Model* const model, cons
         if (partnum == 5) model->mnemonic5 = part;
         if (partnum == 6) model->mnemonic6 = part;
 
-        ptr = strtok(NULL, ",");
+        ptr = flipbip39_strtok(NULL, ",");
     }