diff --git a/include/sys/u8_textprep.h b/include/sys/u8_textprep.h
index 11bf8f4373e0..86161e0aafa0 100644
--- a/include/sys/u8_textprep.h
+++ b/include/sys/u8_textprep.h
@@ -45,7 +45,9 @@ extern "C" {
  */
 #define	U8_STRCMP_CS			(0x00000001)
 #define	U8_STRCMP_CI_UPPER		(0x00000002)
+#if 0
 #define	U8_STRCMP_CI_LOWER		(0x00000004)
+#endif
 
 #define	U8_CANON_DECOMP			(0x00000010)
 #define	U8_COMPAT_DECOMP		(0x00000020)
@@ -57,7 +59,9 @@ extern "C" {
 #define	U8_STRCMP_NFKC			(U8_COMPAT_DECOMP | U8_CANON_COMP)
 
 #define	U8_TEXTPREP_TOUPPER		(U8_STRCMP_CI_UPPER)
+#ifdef U8_STRCMP_CI_LOWER
 #define	U8_TEXTPREP_TOLOWER		(U8_STRCMP_CI_LOWER)
+#endif
 
 #define	U8_TEXTPREP_NFD			(U8_STRCMP_NFD)
 #define	U8_TEXTPREP_NFC			(U8_STRCMP_NFC)
diff --git a/include/sys/u8_textprep_data.h b/include/sys/u8_textprep_data.h
index 3f2564f618cf..6c4c9dfa2b08 100644
--- a/include/sys/u8_textprep_data.h
+++ b/include/sys/u8_textprep_data.h
@@ -27630,6 +27630,7 @@ static const uchar_t u8_case_common_b2_tbl[U8_UNICODE_LATEST + 1][2][256] = {
 
 };
 
+#ifdef U8_STRCMP_CI_LOWER
 static const u8_displacement_t u8_tolower_b3_tbl[U8_UNICODE_LATEST + 1][5][256] = {
 #ifdef U8_UNICODE_320
 	{
@@ -31412,6 +31413,7 @@ static const uchar_t u8_tolower_final_tbl[U8_UNICODE_LATEST + 1][2299] = {
 		0x90, 0x91, 0x8F,
 	},
 };
+#endif
 
 static const u8_displacement_t u8_toupper_b3_tbl[U8_UNICODE_LATEST + 1][5][256] = {
 #ifdef U8_UNICODE_320
diff --git a/module/unicode/u8_textprep.c b/module/unicode/u8_textprep.c
index 37eb848a5288..9164983d9fa2 100644
--- a/module/unicode/u8_textprep.c
+++ b/module/unicode/u8_textprep.c
@@ -531,7 +531,9 @@ do_case_conv(int uv, uchar_t *u8s, uchar_t *s, int sz, boolean_t is_it_toupper)
 
 		for (i = 0; start_id < end_id; start_id++)
 			u8s[i++] = u8_toupper_final_tbl[uv][b3_base + start_id];
-	} else {
+	}
+#ifdef U8_STRCMP_CI_LOWER
+	else {
 		b3_tbl = u8_tolower_b3_tbl[uv][b2][b3].tbl_id;
 		if (b3_tbl == U8_TBL_ELEMENT_NOT_DEF)
 			return ((size_t)sz);
@@ -547,6 +549,7 @@ do_case_conv(int uv, uchar_t *u8s, uchar_t *s, int sz, boolean_t is_it_toupper)
 		for (i = 0; start_id < end_id; start_id++)
 			u8s[i++] = u8_tolower_final_tbl[uv][b3_base + start_id];
 	}
+#endif
 
 	/*
 	 * If i is still zero, that means there is no corresponding character.
@@ -1758,7 +1761,11 @@ do_norm_compare(size_t uv, uchar_t *s1, uchar_t *s2, size_t n1, size_t n2,
 	s2last = s2 + n2;
 
 	is_it_toupper = flag & U8_TEXTPREP_TOUPPER;
+#ifdef U8_STRCMP_CI_LOWER
 	is_it_tolower = flag & U8_TEXTPREP_TOLOWER;
+#else
+	is_it_tolower = 0;
+#endif
 	canonical_decomposition = flag & U8_CANON_DECOMP;
 	compatibility_decomposition = flag & U8_COMPAT_DECOMP;
 	canonical_composition = flag & U8_CANON_COMP;
@@ -1875,12 +1882,18 @@ u8_strcmp(const char *s1, const char *s2, size_t n, int flag, size_t uv,
 	if (flag == 0) {
 		flag = U8_STRCMP_CS;
 	} else {
-		f = flag & (U8_STRCMP_CS | U8_STRCMP_CI_UPPER |
-		    U8_STRCMP_CI_LOWER);
+		f = flag & (U8_STRCMP_CS | U8_STRCMP_CI_UPPER
+#ifdef U8_STRCMP_CI_LOWER
+		    | U8_STRCMP_CI_LOWER
+#endif
+		    );
 		if (f == 0) {
 			flag |= U8_STRCMP_CS;
-		} else if (f != U8_STRCMP_CS && f != U8_STRCMP_CI_UPPER &&
-		    f != U8_STRCMP_CI_LOWER) {
+		} else if (f != U8_STRCMP_CS && f != U8_STRCMP_CI_UPPER
+#ifdef U8_STRCMP_CI_LOWER
+		    && f != U8_STRCMP_CI_LOWER
+#endif
+		    ) {
 			*errnum = EBADF;
 			flag = U8_STRCMP_CS;
 		}
@@ -1913,10 +1926,13 @@ u8_strcmp(const char *s1, const char *s2, size_t n, int flag, size_t uv,
 	if (flag == U8_STRCMP_CI_UPPER) {
 		return (do_case_compare(uv, (uchar_t *)s1, (uchar_t *)s2,
 		    n1, n2, B_TRUE, errnum));
-	} else if (flag == U8_STRCMP_CI_LOWER) {
+	}
+#ifdef U8_STRCMP_CI_LOWER
+	 else if (flag == U8_STRCMP_CI_LOWER) {
 		return (do_case_compare(uv, (uchar_t *)s1, (uchar_t *)s2,
 		    n1, n2, B_FALSE, errnum));
 	}
+#endif
 
 	return (do_norm_compare(uv, (uchar_t *)s1, (uchar_t *)s2, n1, n2,
 	    flag, errnum));
@@ -1950,11 +1966,15 @@ u8_textprep_str(char *inarray, size_t *inlen, char *outarray, size_t *outlen,
 		return ((size_t)-1);
 	}
 
+#ifdef U8_TEXTPREP_TOLOWER
 	f = flag & (U8_TEXTPREP_TOUPPER | U8_TEXTPREP_TOLOWER);
 	if (f == (U8_TEXTPREP_TOUPPER | U8_TEXTPREP_TOLOWER)) {
 		*errnum = EBADF;
 		return ((size_t)-1);
 	}
+#else
+	f = flag & U8_TEXTPREP_TOUPPER;
+#endif
 
 	f = flag & (U8_CANON_DECOMP | U8_COMPAT_DECOMP | U8_CANON_COMP);
 	if (f && f != U8_TEXTPREP_NFD && f != U8_TEXTPREP_NFC &&
@@ -1979,7 +1999,11 @@ u8_textprep_str(char *inarray, size_t *inlen, char *outarray, size_t *outlen,
 	do_not_ignore_null = !(flag & U8_TEXTPREP_IGNORE_NULL);
 	do_not_ignore_invalid = !(flag & U8_TEXTPREP_IGNORE_INVALID);
 	is_it_toupper = flag & U8_TEXTPREP_TOUPPER;
+#ifdef U8_TEXTPREP_TOLOWER
 	is_it_tolower = flag & U8_TEXTPREP_TOLOWER;
+#else
+	is_it_tolower = 0;
+#endif
 
 	ret_val = 0;