minor changes to nexus live build process

updated nexus-exam to wait 15 sec before fetching a new token

live_exam_os/Dockerfile

@@ -27,7 +27,7 @@ RUN make build_nexus-exam SERVER=${server_ip}:${server_port} CERT=${cert} EXAM_U
 #--------------------------------------------------------------------------------------------------------------------
 # Final builder stage that generates the live nexus-exam ISO image
 
-FROM debian:stable-slim
+FROM debian:12
 
 ARG server_ip
 ARG server_port
@@ -35,10 +35,7 @@ ARG cert
 ARG exam_user
 ARG exam_pwd
 
-RUN apt-get update && apt-get install -y \
-      live-build \
-      live-config \
-  && rm -rf /var/lib/apt/lists/*
+RUN apt-get update && apt-get install -y live-build live-config && rm -rf /var/lib/apt/lists/*
 
 WORKDIR /live-default
 

live_exam_os/config/config

@@ -4,7 +4,6 @@ lb config noauto \
      --system live \
      --architectures amd64 \
      --mode debian \
-     --bootloaders grub-efi \
      --parent-distribution bookworm \
      --distribution bookworm \
      --binary-images iso \

src/client/nexus-exam/nexus-exam.go

@@ -143,6 +143,11 @@ func setHeaderToken() {
 
 // Recurrently obtains a new JWT token so that the user session doesn't expire.
 func refreshToken(parent fyne.Window) {
+    // Wait 10 seconds before attempting to refresh the token.
+    // The reason for this delay is that when nexus-exam is launched from
+    // a nexus live image, the wifi interface might not be up yet.
+    time.Sleep(10*time.Second)
+
     for {
         setHeaderToken()
         refreshedToken, err := cmdToken.GetToken()