diff --git a/unit-test/cf_cfdp_s_tests.c b/unit-test/cf_cfdp_s_tests.c
index 0303863d7..e3601c567 100644
--- a/unit-test/cf_cfdp_s_tests.c
+++ b/unit-test/cf_cfdp_s_tests.c
@@ -3612,7 +3612,7 @@ void Test_CF_CFDP_S_Tick_ArmedTimerExpiredAnd_sub_state_EqTo_SEND_WAIT_FOR_EOF_A
     int              *arg_cont                 = NULL;
     uint16            initial_inactivity_timer = Any_uint16();
     uint16            initial_fault_ack_limit  = Any_uint16();
-    uint8             dummy_ack_limit          = Any_uint8();
+    uint8             dummy_ack_limit          = 10;
     CF_Timer_t       *context_CF_Timer_Expired[2];
     CF_Timer_t       *context_CF_Timer_Tick;
 
@@ -3622,7 +3622,7 @@ void Test_CF_CFDP_S_Tick_ArmedTimerExpiredAnd_sub_state_EqTo_SEND_WAIT_FOR_EOF_A
     arg_t->flags.com.ack_timer_armed = 1;
     arg_t->state_data.s.sub_state    = CF_TxSubState_WAIT_FOR_EOF_ACK;
 
-    arg_t->state_data.s.s2.acknak_count = Any_uint8_Except(dummy_ack_limit - 1);
+    arg_t->state_data.s.s2.acknak_count = 5; /* must remain less than ack_limit after increment */
 
     CF_AppData.config_table                                                   = &dummy_config_table;
     CF_AppData.hk.channel_hk[arg_t->chan_num].counters.fault.inactivity_timer = initial_inactivity_timer;
@@ -3692,7 +3692,7 @@ void Test_CF_CFDP_S_Tick_ArmedTimerExpiredAnd_sub_state_EqTo_SEND_WAIT_FOR_EOF_A
     int              *arg_cont                 = NULL;
     uint16            initial_inactivity_timer = Any_uint16();
     uint16            initial_fault_ack_limit  = Any_uint16();
-    uint8             dummy_ack_limit          = Any_uint8();
+    uint8             dummy_ack_limit          = 10;
     CF_Timer_t       *context_CF_Timer_Expired[2];
     CF_Timer_t       *context_CF_Timer_Tick;
     CF_Transaction_t *context_CF_CFDP_ArmAckTimer;
@@ -3703,7 +3703,7 @@ void Test_CF_CFDP_S_Tick_ArmedTimerExpiredAnd_sub_state_EqTo_SEND_WAIT_FOR_EOF_A
     arg_t->flags.com.ack_timer_armed = 1;
     arg_t->state_data.s.sub_state    = CF_TxSubState_WAIT_FOR_EOF_ACK;
 
-    arg_t->state_data.s.s2.acknak_count = Any_uint8_Except(dummy_ack_limit - 1);
+    arg_t->state_data.s.s2.acknak_count = 5; /* must remain less than ack_limit after increment */
 
     CF_AppData.config_table                                                   = &dummy_config_table;
     CF_AppData.hk.channel_hk[arg_t->chan_num].counters.fault.inactivity_timer = initial_inactivity_timer;