diff --git a/bootloader.c b/bootloader.c
index 9f0c5d9..b7c1c16 100644
--- a/bootloader.c
+++ b/bootloader.c
@@ -240,14 +240,14 @@ __attribute__((always_inline)) static inline void synthesize_block(uint32_t bloc
         for (int i = 0; i < 32; i++)
             USB_EP1_IN(i * 2) = ((uint16_t*)INFO_UF2)[i];
     } else if (block == 66 && piece == 1) {
-        for (int i = 0; i < (sizeof(INFO_UF2) - 64 + 1 / 2); i++)
+        for (int i = 0; i < (sizeof(INFO_UF2) - 64 + 1) / 2; i++)
             USB_EP1_IN(i * 2) = ((uint16_t*)INFO_UF2)[32 + i];
-        for (int i = (sizeof(INFO_UF2) + 1 / 2); i < 32; i++)
+        for (int i = (sizeof(INFO_UF2) - 64 + 1) / 2; i < 32; i++)
             USB_EP1_IN(i * 2) = 0;
     } else if (block == 67 && piece == 0) {
-        for (int i = 0; i < (sizeof(INDEX_HTM) + 1 / 2); i++)
+        for (int i = 0; i < (sizeof(INDEX_HTM) + 1) / 2; i++)
             USB_EP1_IN(i * 2) = ((uint16_t*)INDEX_HTM)[i];
-        for (int i = (sizeof(INDEX_HTM) + 1 / 2); i < 32; i++)
+        for (int i = (sizeof(INDEX_HTM) + 1) / 2; i < 32; i++)
             USB_EP1_IN(i * 2) = 0;
     } else {
         for (int i = 0; i < 32; i++)