diff --git a/src/cpu/386_dynarec.c b/src/cpu/386_dynarec.c
index 23f3f1e35..41a61495e 100644
--- a/src/cpu/386_dynarec.c
+++ b/src/cpu/386_dynarec.c
@@ -405,7 +405,7 @@ exec386_dynarec_dyn(void)
             uint64_t mask = (uint64_t) 1 << ((phys_addr >> PAGE_MASK_SHIFT) & PAGE_MASK_MASK);
 #    ifdef USE_NEW_DYNAREC
             int      byte_offset = (phys_addr >> PAGE_BYTE_MASK_SHIFT) & PAGE_BYTE_MASK_OFFSET_MASK;
-            uint64_t byte_mask   = 1ULL << (PAGE_BYTE_MASK_MASK & 0x3f);
+            uint64_t byte_mask   = 1ULL << (phys_addr & PAGE_BYTE_MASK_MASK);
 
             if ((page->code_present_mask & mask) ||
                 ((page->mem != page_ff) && (page->byte_code_present_mask[byte_offset] & byte_mask)))