diff --git a/runtime/include/arch/x86_64/context.h b/runtime/include/arch/x86_64/context.h
index fa8f50f..7bcbce5 100644
--- a/runtime/include/arch/x86_64/context.h
+++ b/runtime/include/arch/x86_64/context.h
@@ -93,7 +93,7 @@ arch_context_switch(struct arch_context *current, struct arch_context *next)
 	   * Check if the variant of the context we're trying to switch to is SLOW (mcontext-based)
 	   * If it is, jump to label 1 to restore the preempted sandbox
 	   */
-	  "cmpq $2, (%%rcx)\n\t" /* if (next->variant == ARCH_CONTEXT_SLOW); */
+	  "cmpq $2, (%%rdx)\n\t" /* if (next->variant == ARCH_CONTEXT_SLOW); */
 	  "je 1f\n\t"            /* 	goto 1; restore the existing sandbox using mcontext */
 
 	  /*
diff --git a/runtime/src/arch_context.c b/runtime/src/arch_context.c
index c0eb746..a1851a9 100644
--- a/runtime/src/arch_context.c
+++ b/runtime/src/arch_context.c
@@ -11,7 +11,6 @@
  */
 void __attribute__((noinline)) __attribute__((noreturn)) arch_context_mcontext_restore(void)
 {
-	debuglog("Sending SIGUSR1");
 	pthread_kill(pthread_self(), SIGUSR1);
 	assert(false);
 }
diff --git a/runtime/src/software_interrupt.c b/runtime/src/software_interrupt.c
index 3eeac2a..7a93a8a 100644
--- a/runtime/src/software_interrupt.c
+++ b/runtime/src/software_interrupt.c
@@ -125,8 +125,8 @@ software_interrupt_handle_signals(int signal_type, siginfo_t *signal_info, void
 
 		/* Extra checks to verify that preemption properly set context state */
 		assert(current_sandbox->ctxt.variant == ARCH_CONTEXT_SLOW);
-		assert(current_sandbox->ctxt.regs[UREG_RSP] != 0);
-		assert(current_sandbox->ctxt.regs[UREG_RIP] != 0);
+		assert(current_sandbox->ctxt.regs[UREG_RSP] == 0);
+		assert(current_sandbox->ctxt.regs[UREG_RIP] == 0);
 
 		software_interrupt_SIGUSR_count++;
 		debuglog("usr1:%d\n", software_interrupt_SIGUSR_count);