diff --git a/lib/extensions/spe/spe.c b/lib/extensions/spe/spe.c
index 236b102..2c25a9d 100644
--- a/lib/extensions/spe/spe.c
+++ b/lib/extensions/spe/spe.c
@@ -26,10 +26,13 @@
 	uint64_t v;
 
 	/*
-	 * MDCR_EL2.NSPB (ARM v8.2): SPE enabled in Non-secure state
+	 * MDCR_EL3.NSPB (ARM v8.2): SPE enabled in Non-secure state
 	 * and disabled in secure state. Accesses to SPE registers at
 	 * S-EL1 generate trap exceptions to EL3.
 	 *
+	 * MDCR_EL3.NSPBE: Profiling Buffer uses Non-secure Virtual Addresses.
+	 * When FEAT_RME is not implemented, this field is RES0.
+	 *
 	 * MDCR_EL3.EnPMSN (ARM v8.7): Do not trap access to PMSNEVFR_EL1
 	 * register at NS-EL1 or NS-EL2 to EL3 if FEAT_SPEv1p2 is implemented.
 	 * Setting this bit to 1 doesn't have any effect on it when
@@ -37,6 +40,7 @@
 	 */
 	v = read_mdcr_el3();
 	v |= MDCR_NSPB(MDCR_NSPB_EL1) | MDCR_EnPMSN_BIT;
+	v &= ~(MDCR_NSPBE_BIT);
 	write_mdcr_el3(v);
 }
 
diff --git a/lib/extensions/trf/aarch32/trf.c b/lib/extensions/trf/aarch32/trf.c
index e13b4db..321c089 100644
--- a/lib/extensions/trf/aarch32/trf.c
+++ b/lib/extensions/trf/aarch32/trf.c
@@ -16,9 +16,9 @@
 
 	/*
 	 * Allow access of trace filter control registers from
-	 * non-monitor mode
+	 * non-monitor mode.
 	 */
 	val = read_sdcr();
-	val &= ~SDCR_TTRF_BIT;
+	val &= ~(SDCR_TTRF_BIT);
 	write_sdcr(val);
 }
diff --git a/lib/extensions/trf/aarch64/trf.c b/lib/extensions/trf/aarch64/trf.c
index f681b28..83fbf85 100644
--- a/lib/extensions/trf/aarch64/trf.c
+++ b/lib/extensions/trf/aarch64/trf.c
@@ -14,12 +14,16 @@
 	u_register_t val;
 
 	/*
+	 * MDCR_EL3.STE = b0
+	 * Trace prohibited in Secure state unless overridden by the
+	 * IMPLEMENTATION DEFINED authentication interface.
+	 *
 	 * MDCR_EL3.TTRF = b0
 	 * Allow access of trace filter control registers from NS-EL2
 	 * and NS-EL1 when NS-EL2 is implemented but not used
 	 */
 	val = read_mdcr_el3();
-	val &= ~MDCR_TTRF_BIT;
+	val &= ~(MDCR_STE_BIT | MDCR_TTRF_BIT);
 	write_mdcr_el3(val);
 }