diff --git a/parser.c b/parser.c
index a009def..a0f7955 100644
--- a/parser.c
+++ b/parser.c
@@ -257,7 +257,7 @@ static struct symbol *qmi_identifier_parse(char *buf, size_t size, char ch)
 /* Used for parsing octal numbers */
 static int isodigit(int c)
 {
-	return isdigit(c) && c < '9';
+	return isdigit(c) && c < '8';
 }
 
 /* Extract a number from input into the given buffer; return base */
diff --git a/tests/bad_octal.qmi b/tests/bad_octal.qmi
index 10c43be..df3a826 100644
--- a/tests/bad_octal.qmi
+++ b/tests/bad_octal.qmi
@@ -7,7 +7,7 @@ struct qmi_result {
 
 request test_request {
 	# Note that '8' is not a valid octal digit
-	optional test_struct foo = 028;
+	optional u32 foo = 028;
 } = 0x23;
 
 response test_response {