diff --git a/crypto_kem/ntruhps2048509/META.yml b/crypto_kem/ntruhps2048509/META.yml
index 2da9d2d5..043d9686 100644
--- a/crypto_kem/ntruhps2048509/META.yml
+++ b/crypto_kem/ntruhps2048509/META.yml
@@ -23,9 +23,9 @@ auxiliary-submitters:
   - Zhenfei Zhang
 implementations:
     - name: clean
-      version: https://github.com/jschanck/ntru/tree/4699d70a reference implementation
+      version: https://github.com/jschanck/ntru/tree/00f73a7f reference implementation
     - name: avx2
-      version: https://github.com/jschanck/ntru/tree/4699d70a avx2 implementation
+      version: https://github.com/jschanck/ntru/tree/00f73a7f avx2 implementation
       supported_platforms:
           - architecture: x86_64
             operating_systems:
diff --git a/crypto_kem/ntruhps2048509/clean/poly_s3_inv.c b/crypto_kem/ntruhps2048509/clean/poly_s3_inv.c
index e6b85690..92b08480 100644
--- a/crypto_kem/ntruhps2048509/clean/poly_s3_inv.c
+++ b/crypto_kem/ntruhps2048509/clean/poly_s3_inv.c
@@ -7,7 +7,7 @@ static inline uint8_t mod3(uint8_t a) { /* a between 0 and 9 */
     a = (a >> 2) + (a & 3); /* between 0 and 4 */
     t = a - 3;
     c = t >> 5;
-    return t ^ (c & (a ^ t));
+    return (uint8_t) (t ^ (c & (a ^ t)));
 }
 
 /* return -1 if x<0 and y<0; otherwise return 0 */
diff --git a/crypto_kem/ntruhps2048677/META.yml b/crypto_kem/ntruhps2048677/META.yml
index 8f3c9c9c..8fbbd05f 100644
--- a/crypto_kem/ntruhps2048677/META.yml
+++ b/crypto_kem/ntruhps2048677/META.yml
@@ -23,9 +23,9 @@ auxiliary-submitters:
   - Zhenfei Zhang
 implementations:
     - name: clean
-      version: https://github.com/jschanck/ntru/tree/4699d70a reference implementation
+      version: https://github.com/jschanck/ntru/tree/00f73a7f reference implementation
     - name: avx2
-      version: https://github.com/jschanck/ntru/tree/4699d70a avx2 implementation
+      version: https://github.com/jschanck/ntru/tree/00f73a7f avx2 implementation
       supported_platforms:
           - architecture: x86_64
             operating_systems:
diff --git a/crypto_kem/ntruhps2048677/clean/poly_s3_inv.c b/crypto_kem/ntruhps2048677/clean/poly_s3_inv.c
index 099a80d4..3412f136 100644
--- a/crypto_kem/ntruhps2048677/clean/poly_s3_inv.c
+++ b/crypto_kem/ntruhps2048677/clean/poly_s3_inv.c
@@ -7,7 +7,7 @@ static inline uint8_t mod3(uint8_t a) { /* a between 0 and 9 */
     a = (a >> 2) + (a & 3); /* between 0 and 4 */
     t = a - 3;
     c = t >> 5;
-    return t ^ (c & (a ^ t));
+    return (uint8_t) (t ^ (c & (a ^ t)));
 }
 
 /* return -1 if x<0 and y<0; otherwise return 0 */
diff --git a/crypto_kem/ntruhps4096821/META.yml b/crypto_kem/ntruhps4096821/META.yml
index 96c97793..9da1e89b 100644
--- a/crypto_kem/ntruhps4096821/META.yml
+++ b/crypto_kem/ntruhps4096821/META.yml
@@ -23,9 +23,9 @@ auxiliary-submitters:
   - Zhenfei Zhang
 implementations:
     - name: clean
-      version: https://github.com/jschanck/ntru/tree/4699d70a reference implementation
+      version: https://github.com/jschanck/ntru/tree/00f73a7f reference implementation
     - name: avx2
-      version: https://github.com/jschanck/ntru/tree/4699d70a avx2 implementation
+      version: https://github.com/jschanck/ntru/tree/00f73a7f avx2 implementation
       supported_platforms:
           - architecture: x86_64
             operating_systems:
diff --git a/crypto_kem/ntruhps4096821/clean/poly_s3_inv.c b/crypto_kem/ntruhps4096821/clean/poly_s3_inv.c
index 3369cf1c..0f6ec95c 100644
--- a/crypto_kem/ntruhps4096821/clean/poly_s3_inv.c
+++ b/crypto_kem/ntruhps4096821/clean/poly_s3_inv.c
@@ -7,7 +7,7 @@ static inline uint8_t mod3(uint8_t a) { /* a between 0 and 9 */
     a = (a >> 2) + (a & 3); /* between 0 and 4 */
     t = a - 3;
     c = t >> 5;
-    return t ^ (c & (a ^ t));
+    return (uint8_t) (t ^ (c & (a ^ t)));
 }
 
 /* return -1 if x<0 and y<0; otherwise return 0 */
diff --git a/crypto_kem/ntruhrss701/META.yml b/crypto_kem/ntruhrss701/META.yml
index a9a1ba77..36617929 100644
--- a/crypto_kem/ntruhrss701/META.yml
+++ b/crypto_kem/ntruhrss701/META.yml
@@ -23,9 +23,9 @@ auxiliary-submitters:
   - Zhenfei Zhang
 implementations:
     - name: clean
-      version: https://github.com/jschanck/ntru/tree/4699d70a reference implementation
+      version: https://github.com/jschanck/ntru/tree/00f73a7f reference implementation
     - name: avx2
-      version: https://github.com/jschanck/ntru/tree/4699d70a avx2 implementation
+      version: https://github.com/jschanck/ntru/tree/00f73a7f avx2 implementation
       supported_platforms:
           - architecture: x86_64
             operating_systems:
diff --git a/crypto_kem/ntruhrss701/clean/poly_s3_inv.c b/crypto_kem/ntruhrss701/clean/poly_s3_inv.c
index d4039d23..6100a08f 100644
--- a/crypto_kem/ntruhrss701/clean/poly_s3_inv.c
+++ b/crypto_kem/ntruhrss701/clean/poly_s3_inv.c
@@ -7,7 +7,7 @@ static inline uint8_t mod3(uint8_t a) { /* a between 0 and 9 */
     a = (a >> 2) + (a & 3); /* between 0 and 4 */
     t = a - 3;
     c = t >> 5;
-    return t ^ (c & (a ^ t));
+    return (uint8_t) (t ^ (c & (a ^ t)));
 }
 
 /* return -1 if x<0 and y<0; otherwise return 0 */