diff --git a/src/controller/ha.h b/src/controller/ha.h
index 07cba6a5..30b6e2c9 100644
--- a/src/controller/ha.h
+++ b/src/controller/ha.h
@@ -22,6 +22,7 @@
 #include <pthread.h>
 #include <stdatomic.h>
 #include <stdint.h>
+#include <string.h>
 #include <time.h>
 #include <unistd.h>
 
@@ -45,11 +46,22 @@ static inline uint64_t xorshift64_next(uint64_t *state)
 
 static inline void ha_seed_jitter(uint64_t *seed, int my_priority)
 {
+    uint8_t buf[8] = {0};
     int fd = open("/dev/urandom", O_RDONLY);
     if (fd >= 0) {
-        if (read(fd, seed, 8) == 8 && *seed != 0) { close(fd); return; }
+        ssize_t n = 0;
+        while (n < 8) {
+            ssize_t r = read(fd, buf + n, (size_t)(8 - n));
+            if (r <= 0) break;
+            n += r;
+        }
         close(fd);
+        if (n == 8) {
+            memcpy(seed, buf, 8);
+            if (*seed != 0) return;
+        }
     }
+    /* Fallback: monotonic clock + priority + pid mixing */
     struct timespec ts;
     clock_gettime(CLOCK_MONOTONIC, &ts);
     *seed = (uint64_t)ts.tv_nsec
diff --git a/src/include/byteorder.h b/src/include/byteorder.h
index 1010afc5..e37afb62 100644
--- a/src/include/byteorder.h
+++ b/src/include/byteorder.h
@@ -1,7 +1,24 @@
 #pragma once
-/* Portable be64toh() for non-glibc or pre-2.25 targets. */
+/* Portable be64toh() — big-endian to host byte order conversion. */
 #if defined(__linux__)
+#  ifndef _DEFAULT_SOURCE
+#    define _DEFAULT_SOURCE 1
+#  endif
+#  ifndef _BSD_SOURCE
+#    define _BSD_SOURCE 1
+#  endif
 #  include <endian.h>
+#  ifndef be64toh
+   /* musl and some older glibc: fall back to builtin */
+#  include <stdint.h>
+static inline uint64_t be64toh(uint64_t x) {
+#    if __BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__
+    return __builtin_bswap64(x);
+#    else
+    return x;
+#    endif
+}
+#  endif /* be64toh */
 #elif defined(__APPLE__)
 #  include <machine/endian.h>
 #  include <libkern/OSByteOrder.h>