diff --git a/VAX/vax_cpu.c b/VAX/vax_cpu.c
index 1b4dd90e..945d34f0 100644
--- a/VAX/vax_cpu.c
+++ b/VAX/vax_cpu.c
@@ -492,7 +492,7 @@ REG cpu_reg[] = {
 MTAB cpu_mod[] = {
     { UNIT_CONH, 0, "HALT to SIMH", "SIMHALT", NULL, NULL, NULL, "Set HALT to trap to simulator" },
     { UNIT_CONH, UNIT_CONH, "HALT to console", "CONHALT", NULL, NULL, NULL, "Set HALT to trap to console ROM" },
-    { MTAB_XTD|MTAB_VDV, 0, "IDLE", "IDLE={VMS|ULTRIX|NETBSD|OPENBSD|ULTRIXOLD|OPENBSDOLD|QUASIJARUS|32V|ALL}", &cpu_set_idle, &cpu_show_idle, NULL, "Display idle detection mode" },
+    { MTAB_XTD|MTAB_VDV, 0, "IDLE", "IDLE={VMS|ULTRIX|NETBSD|OPENBSD|ULTRIXOLD|OPENBSDOLD|QUASIJARUS|32V|ELN|ALL}", &cpu_set_idle, &cpu_show_idle, NULL, "Display idle detection mode" },
     { MTAB_XTD|MTAB_VDV, 0, NULL, "NOIDLE", &sim_clr_idle, NULL, NULL,  "Disables idle detection" },
     MEM_MODIFIERS,   /* Model specific memory modifiers from vaxXXX_defs.h */
     { MTAB_XTD|MTAB_VDV|MTAB_NMO|MTAB_SHP, 0, "HISTORY", "HISTORY",
@@ -2216,10 +2216,14 @@ for ( ;; ) {
     case BEQL:
         if (cc & CC_Z) {                                /* br if Z = 1 */
             BRANCHB (brdisp);
-            if (((PSL & PSL_IS) != 0) &&                /* on IS? */
-                (PSL_GETIPL (PSL) == 0x1F) &&           /* at IPL 31 */
-                (mapen == 0) &&                         /* Running from ROM */
-                (fault_PC == 0x2004361B))               /* Boot ROM Character Prompt */
+            if ((((PSL & PSL_IS) != 0) &&               /* on IS? */
+                 (PSL_GETIPL (PSL) == 0x1F) &&          /* at IPL 31 */
+                 (mapen == 0) &&                        /* Running from ROM */
+                 (fault_PC == 0x2004361B)) ||           /* Boot ROM Character Prompt */
+                ((cpu_idle_mask & VAX_IDLE_ELN) &&      /* VAXELN Idle? */
+                 (PSL & PSL_IS) &&                      /* on IS? */
+                 (brdisp == 0xFA) &&                    /* Branch to prior TSTL */
+                 (PSL_GETIPL (PSL) == 0x4)))            /* at IPL 4 */
                 cpu_idle();
             }
         break;
@@ -3524,7 +3528,8 @@ static struct os_idle os_tab[] = {
     { "OPENBSD", VAX_IDLE_BSDNEW },
     { "QUASIJARUS", VAX_IDLE_QUAD },
     { "32V", VAX_IDLE_VMS },
-    { "ALL", VAX_IDLE_VMS|VAX_IDLE_ULTOLD|VAX_IDLE_ULT|VAX_IDLE_ULT1X|VAX_IDLE_QUAD|VAX_IDLE_BSDNEW },
+    { "ELN", VAX_IDLE_ELN },
+    { "ALL", VAX_IDLE_VMS|VAX_IDLE_ULTOLD|VAX_IDLE_ULT|VAX_IDLE_ULT1X|VAX_IDLE_QUAD|VAX_IDLE_BSDNEW|VAX_IDLE_ELN },
     { NULL, 0 }
     };
 
@@ -3617,7 +3622,7 @@ fprintf (st, "      -u      interpret address as virtual, user mode\n\n");
 fprintf (st, "The CPU attempts to detect when the simulator is idle.  When idle, the\n");
 fprintf (st, "simulator does not use any resources on the host system.  Idle detection is\n");
 fprintf (st, "controlled by the SET IDLE and SET NOIDLE commands:\n\n");
-fprintf (st, "   sim> SET CPU IDLE{=VMS|ULTRIX|NETBSD|FREEBSD|32V|ALL}\n");
+fprintf (st, "   sim> SET CPU IDLE{=VMS|ULTRIX|NETBSD|FREEBSD|32V|ELN|ALL}\n");
 fprintf (st, "                                        enable idle detection\n");
 fprintf (st, "   sim> SET CPU NOIDLE                  disable idle detection\n\n");
 fprintf (st, "Idle detection is disabled by default.  Unless ALL is specified, idle\n");
diff --git a/VAX/vax_defs.h b/VAX/vax_defs.h
index eb553acf..e7444500 100644
--- a/VAX/vax_defs.h
+++ b/VAX/vax_defs.h
@@ -734,6 +734,7 @@ enum opcodes {
 #define VAX_IDLE_QUAD       0x10
 #define VAX_IDLE_BSDNEW     0x20
 #define VAX_IDLE_SYSV       0x40
+#define VAX_IDLE_ELN        0x80    /* VAXELN */
 extern uint32 cpu_idle_mask;                            /* idle mask */
 void cpu_idle (void);