diff -Naur busybox-1.13.3.orig/init/init.c busybox-1.13.3/init/init.c
--- busybox-1.13.3.orig/init/init.c	2009-05-29 17:37:17.000000000 +0200
+++ busybox-1.13.3/init/init.c	2009-05-29 17:31:19.000000000 +0200
@@ -820,6 +820,87 @@
 }
 #endif
 
+#if defined(__FreeBSD_kernel__)
+#define BAD_OPEN_MESSAGE					\
+"Error: /proc must be mounted\n"				\
+"  To mount /proc at boot you need an /etc/fstab line like:\n"	\
+"      /proc   /proc   proc    defaults\n"			\
+"  In the meantime, run \"mount /proc /proc -t proc\"\n"
+
+#define MEMINFO_FILE "/proc/meminfo"
+static int meminfo_fd = -1;
+
+static char buf[1024];
+
+/* This macro opens filename only if necessary and seeks to 0 so
+ * that successive calls to the functions are more efficient.
+ * It also reads the current contents of the file into the global buf.
+ */
+#define FILE_TO_BUF(filename, fd) do{				\
+    static int local_n;						\
+    if (fd == -1 && (fd = open(filename, O_RDONLY)) == -1) {	\
+	fputs(BAD_OPEN_MESSAGE, stderr);			\
+	fflush(NULL);						\
+	_exit(102);						\
+    }								\
+    lseek(fd, 0L, SEEK_SET);					\
+    if ((local_n = read(fd, buf, sizeof buf - 1)) < 0) {	\
+	perror(filename);					\
+	fflush(NULL);						\
+	_exit(103);						\
+    }								\
+    buf[local_n] = '\0';					\
+}while(0)
+
+typedef struct mem_table_struct {
+  const char *name;     /* memory type name */
+  unsigned long *slot; /* slot in return struct */
+} mem_table_struct;
+
+static int compare_mem_table_structs(const void *a, const void *b){
+  return strcmp(((const mem_table_struct*)a)->name,((const mem_table_struct*)b)->name);
+}
+
+/* old but still kicking -- the important stuff */
+unsigned long kb_main_total;
+
+static void meminfo(void){
+  char namebuf[16]; /* big enough to hold any row name */
+  mem_table_struct findme = { namebuf, NULL};
+  mem_table_struct *found;
+  char *head;
+  char *tail;
+  static const mem_table_struct mem_table[] = {
+  {"MemTotal",     &kb_main_total},   // important
+  };
+  const int mem_table_count = sizeof(mem_table)/sizeof(mem_table_struct);
+
+  FILE_TO_BUF(MEMINFO_FILE,meminfo_fd);
+
+  head = buf;
+  for(;;){
+    tail = strchr(head, ':');
+    if(!tail) break;
+    *tail = '\0';
+    if(strlen(head) >= sizeof(namebuf)){
+      head = tail+1;
+      goto nextline;
+    }
+    strcpy(namebuf,head);
+    found = bsearch(&findme, mem_table, mem_table_count,
+        sizeof(mem_table_struct), compare_mem_table_structs
+    );
+    head = tail+1;
+    if(!found) goto nextline;
+    *(found->slot) = strtoul(head,&tail,10);
+nextline:
+    tail = strchr(head, '\n');
+    if(!tail) break;
+    head = tail+1;
+  }
+}
+#endif
+
 int init_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
 int init_main(int argc UNUSED_PARAM, char **argv)
 {
@@ -881,10 +962,19 @@
 
 	/* Make sure there is enough memory to do something useful. */
 	if (ENABLE_SWAPONOFF) {
+#if defined(__linux__)
 		struct sysinfo info;
 
 		if (!sysinfo(&info) &&
 			(info.mem_unit ? : 1) * (long long)info.totalram < 1024*1024)
+#elif defined(__FreeBSD_kernel__)
+# define S(X) ( ((unsigned long long)(X) << 10) >> shift)
+		const int shift = 10;
+
+		meminfo();
+
+		if (S(kb_main_total) < 1024*1024)
+#endif
 		{
 			message(L_CONSOLE, "Low memory, forcing swapon");
 			/* swapon -a requires /proc typically */