Build and program starting fixes

brick/uf2daemon/fat.c

@@ -666,21 +666,26 @@ void stopLMS() {
     closedir(dir);
 
     if (lmsPid) {
-        DBG("SIGSTOP to lmsPID=%d", lmsPid);
+        DBG("SIGSTOP to lmsPID=%d\n", lmsPid);
         kill(lmsPid, SIGSTOP);
+    } else {
+        DBG("LMS not found\n");
     }
 }
 
 void waitAndContinue() {
+    stopLMS();
     for (int fd = 3; fd < 9999; ++fd)
         close(fd);
     pid_t child = fork();
     if (child == 0) {
-        execl(elfPath, elfPath, "--msd");
+        DBG("start %s\n", elfPath);
+        execl(elfPath, elfPath, "--msd", (char*) NULL);
         exit(128);
     }
     int status;
     waitpid(child, &status, 0);
+    DBG("re-start LMS\n");
     if (lmsPid)
         kill(lmsPid, SIGCONT);
     exit(0);

brick/uf2daemon/main.c

@@ -133,6 +133,7 @@ void runNBD() {
     reply.error = htonl(0);
 
     for (;;) {
+        nbd_ioctl(BLKFLSBUF, 0); // flush buffers - we don't want the kernel to cache the writes
         int nread = read(sock, &request, sizeof(request));
 
         if (nread < 0) {
@@ -199,7 +200,9 @@ int main() {
 
         if (!WIFEXITED(wstatus) || WEXITSTATUS(wstatus) != 0) {
             LOG("abnormal child return, %d", child);
-            sleep(3);
+            sleep(5);
+        } else {
+            sleep(2);
         }
     }