diff --git a/src/adiv5_jtagdp.c b/src/adiv5_jtagdp.c
index 693b94e..4306101 100644
--- a/src/adiv5_jtagdp.c
+++ b/src/adiv5_jtagdp.c
@@ -92,10 +92,14 @@ static uint32_t adiv5_jtagdp_low_access(ADIv5_DP_t *dp, uint8_t APnDP, uint8_t R
 
 	jtag_dev_write_ir(dp->dev, APnDP?IR_APACC:IR_DPACC);
 
+	int tries = 1000;
 	do {
 		jtag_dev_shift_dr(dp->dev, (uint8_t*)&response, (uint8_t*)&request, 35);
 		ack = response & 0x07;
-	} while(ack == JTAGDP_ACK_WAIT);
+	} while(--tries && (ack == JTAGDP_ACK_WAIT));
+
+	if (dp->allow_timeout && (ack == JTAGDP_ACK_WAIT))
+		return 0;
 
 	if((ack != JTAGDP_ACK_OK)) {
 		/* Fatal error if invalid ACK response */
diff --git a/src/adiv5_swdp.c b/src/adiv5_swdp.c
index 839127d..c021190 100644
--- a/src/adiv5_swdp.c
+++ b/src/adiv5_swdp.c
@@ -135,8 +135,8 @@ static uint32_t adiv5_swdp_low_access(ADIv5_DP_t *dp, uint8_t APnDP, uint8_t RnW
 		ack = swdptap_seq_in(3);
 	} while(--tries && ack == SWDP_ACK_WAIT);
 
-	if(!tries)
-		PLATFORM_FATAL_ERROR(1);
+	if (dp->allow_timeout && (ack == SWDP_ACK_WAIT))
+		return 0;
 
 	if(ack == SWDP_ACK_FAULT) {
 		dp->fault = 1;
diff --git a/src/cortexm.c b/src/cortexm.c
index 7819598..a8bb34b 100644
--- a/src/cortexm.c
+++ b/src/cortexm.c
@@ -584,6 +584,7 @@ cortexm_halt_request(struct target_s *target)
 {
 	ADIv5_AP_t *ap = adiv5_target_ap(target);
 
+	ap->dp->allow_timeout = false;
 	adiv5_ap_mem_write(ap, CORTEXM_DHCSR,
 		CORTEXM_DHCSR_DBGKEY | CORTEXM_DHCSR_C_HALT | CORTEXM_DHCSR_C_DEBUGEN);
 }
@@ -596,6 +597,8 @@ cortexm_halt_wait(struct target_s *target)
 	if (!(adiv5_ap_mem_read(ap, CORTEXM_DHCSR) & CORTEXM_DHCSR_S_HALT))
 		return 0;
 
+	ap->dp->allow_timeout = false;
+
 	/* We've halted.  Let's find out why. */
 	uint32_t dfsr = adiv5_ap_mem_read(ap, CORTEXM_DFSR);
 	adiv5_ap_mem_write(ap, CORTEXM_DFSR, dfsr); /* write back to reset */
@@ -654,6 +657,7 @@ cortexm_halt_resume(struct target_s *target, bool step)
 	}
 
 	adiv5_ap_mem_write(ap, CORTEXM_DHCSR, dhcsr);
+	ap->dp->allow_timeout = true;
 }
 
 static int cortexm_fault_unwind(struct target_s *target)
diff --git a/src/include/adiv5.h b/src/include/adiv5.h
index 1bfb5a1..64b6a28 100644
--- a/src/include/adiv5.h
+++ b/src/include/adiv5.h
@@ -106,6 +106,8 @@ typedef struct ADIv5_DP_s {
 
 	uint32_t idcode;
 
+	bool allow_timeout;
+
 	void (*dp_write)(struct ADIv5_DP_s *dp, uint8_t addr, uint32_t value);
 	uint32_t (*dp_read)(struct ADIv5_DP_s *dp, uint8_t addr);