diff --git a/arch/arm/src/armv7-a/arm_blocktask.c b/arch/arm/src/armv7-a/arm_blocktask.c
index 61cce48de27..8fdbef00a36 100644
--- a/arch/arm/src/armv7-a/arm_blocktask.c
+++ b/arch/arm/src/armv7-a/arm_blocktask.c
@@ -1,7 +1,7 @@
 /****************************************************************************
  * arch/arm/src/armv7-a/up_blocktask.c
  *
- *   Copyright (C) 2013-2015 Gregory Nutt. All rights reserved.
+ *   Copyright (C) 2013-2015, 2018 Gregory Nutt. All rights reserved.
  *   Author: Gregory Nutt <gnutt@nuttx.org>
  *
  * Redistribution and use in source and binary forms, with or without
@@ -76,8 +76,21 @@
 
 void up_block_task(struct tcb_s *tcb, tstate_t task_state)
 {
-  struct tcb_s *rtcb = this_task();
+  struct tcb_s *rtcb;
   bool switch_needed;
+#ifdef CONFIG_SMP
+  int cpu;
+
+  /* Get the TCB of the currently executing task on this CPU (avoid using
+   * this_task() because the TCBs may be in an inappropriate state right
+   * now).
+   */
+
+  cpu  = this_cpu();
+  rtcb = current_task(cpu);
+#else
+  rtcb = this_task();
+#endif
 
   /* Verify that the context switch can be performed */
 
@@ -128,7 +141,11 @@ void up_block_task(struct tcb_s *tcb, tstate_t task_state)
            * of the ready-to-run task list.
            */
 
+#ifdef CONFIG_SMP
+          rtcb = current_task(cpu);
+#else
           rtcb = this_task();
+#endif
 
           /* Reset scheduler parameters */
 
@@ -152,7 +169,11 @@ void up_block_task(struct tcb_s *tcb, tstate_t task_state)
            * of the ready-to-run task list.
            */
 
+#ifdef CONFIG_SMP
+          rtcb = current_task(cpu);
+#else
           rtcb = this_task();
+#endif
 
 #ifdef CONFIG_ARCH_ADDRENV
           /* Make sure that the address environment for the previously
diff --git a/arch/arm/src/armv7-a/arm_unblocktask.c b/arch/arm/src/armv7-a/arm_unblocktask.c
index a9b0da6d2f8..906d33796b6 100644
--- a/arch/arm/src/armv7-a/arm_unblocktask.c
+++ b/arch/arm/src/armv7-a/arm_unblocktask.c
@@ -1,7 +1,7 @@
 /****************************************************************************
  *  arch/arm/src/armv7-a/arm_unblocktask.c
  *
- *   Copyright (C) 2013-2015 Gregory Nutt. All rights reserved.
+ *   Copyright (C) 2013-2015, 2018 Gregory Nutt. All rights reserved.
  *   Author: Gregory Nutt <gnutt@nuttx.org>
  *
  * Redistribution and use in source and binary forms, with or without
@@ -71,7 +71,20 @@
 
 void up_unblock_task(struct tcb_s *tcb)
 {
-  struct tcb_s *rtcb = this_task();
+  struct tcb_s *rtcb;
+#ifdef CONFIG_SMP
+  int cpu;
+
+  /* Get the TCB of the currently executing task on this CPU (avoid using
+   * this_task() because the TCBs may be in an inappropriate state right
+   * now).
+   */
+
+  cpu  = this_cpu();
+  rtcb = current_task(cpu);
+#else
+  rtcb = this_task();
+#endif
 
   /* Verify that the context switch can be performed */
 
@@ -110,7 +123,11 @@ void up_unblock_task(struct tcb_s *tcb)
            * of the ready-to-run task list.
            */
 
+#ifdef CONFIG_SMP
+          rtcb = current_task(cpu);
+#else
           rtcb = this_task();
+#endif
 
           /* Update scheduler parameters */
 
@@ -136,7 +153,11 @@ void up_unblock_task(struct tcb_s *tcb)
            * ready-to-run task list.
            */
 
+#ifdef CONFIG_SMP
+          rtcb = current_task(cpu);
+#else
           rtcb = this_task();
+#endif
 
 #ifdef CONFIG_ARCH_ADDRENV
           /* Make sure that the address environment for the previously
diff --git a/configs/sabre-6quad/README.txt b/configs/sabre-6quad/README.txt
index 482e07c542b..462ffeffeda 100644
--- a/configs/sabre-6quad/README.txt
+++ b/configs/sabre-6quad/README.txt
@@ -121,6 +121,34 @@ Status
 2016-12-07:  Just a note to remind myself.  The PL310 L2 cache has *not*
   yet been enabled.
 
+2018-02-06:  Revisited SMP to see how has been broken due to bit rot.
+  Several fixes were needed mostly due to:  (1) The new version of
+  this_task() that calls sched_lock() and sched_unlock(), and (2) to
+  deferred setting g_cpu_irqlock().  That latter setting is now deferred
+  until sched_resume_scheduler() runs.  This means several changes similar
+  to the following were necessary in order to get things working from:
+
+    struct tcb_s *rtcb = this_task();
+
+  To:
+
+    struct tcb_s *rtcb;
+  #ifdef CONFIG_SMP
+    int cpu;
+
+    /* Get the TCB of the currently executing task on this CPU (avoid using
+     * this_task() because the TCBs may be in an inappropriate state right
+     * now).
+     */
+
+    cpu  = this_cpu();
+    rtcb = current_task(cpu);
+  #else
+    rtcb = this_task();
+  #endif
+
+  At present, the NSH prompt does come up but there there still hangs that
+  must be addressed.
 Platform Features
 =================