diff --git a/docs/design/cpu-specific-build-macros.rst b/docs/design/cpu-specific-build-macros.rst
index 9db29e6..53b54b8 100644
--- a/docs/design/cpu-specific-build-macros.rst
+++ b/docs/design/cpu-specific-build-macros.rst
@@ -317,6 +317,10 @@
    CPU. This needs to be enabled for revisions r0p0, r1p0, r1p1, and r1p2, and
    it is still open.
 
+-  ``ERRATA_A78_2742426``: This applies erratum 2742426 workaround to Cortex-A78
+   CPU. This needs to be enabled for revisions r0p0, r1p0, r1p1 and r1p2 and
+   it is still open.
+
 -  ``ERRATA_A78_2772019``: This applies errata 2772019 workaround to Cortex-A78
    CPU. This needs to be enabled for revisions r0p0, r1p0, r1p1, and r1p2, and
    it is still open.
diff --git a/include/lib/cpus/aarch64/cortex_a78.h b/include/lib/cpus/aarch64/cortex_a78.h
index fb325b6..66f565d 100644
--- a/include/lib/cpus/aarch64/cortex_a78.h
+++ b/include/lib/cpus/aarch64/cortex_a78.h
@@ -20,8 +20,8 @@
 #define CORTEX_A78_CPUECTLR_EL1				S3_0_C15_C1_4
 #define CORTEX_A78_CPUECTLR_EL1_BIT_8			(ULL(1) << 8)
 #define CORTEX_A78_CPUECTLR_EL1_PF_MODE_CNSRV		ULL(3)
-#define CPUECTLR_EL1_PF_MODE_LSB				U(6)
-#define CPUECTLR_EL1_PF_MODE_WIDTH				U(2)
+#define CPUECTLR_EL1_PF_MODE_LSB			U(6)
+#define CPUECTLR_EL1_PF_MODE_WIDTH			U(2)
 
 /*******************************************************************************
  * CPU Power Control register specific definitions
@@ -42,6 +42,8 @@
 
 #define CORTEX_A78_ACTLR3_EL1				S3_0_C15_C1_2
 
+#define CORTEX_A78_ACTLR5_EL1				S3_0_C15_C9_0
+
 /*******************************************************************************
  * CPU Activity Monitor Unit register specific definitions.
  ******************************************************************************/
diff --git a/lib/cpus/aarch64/cortex_a78.S b/lib/cpus/aarch64/cortex_a78.S
index a3932e8..421509d 100644
--- a/lib/cpus/aarch64/cortex_a78.S
+++ b/lib/cpus/aarch64/cortex_a78.S
@@ -327,6 +327,36 @@
 endfunc check_errata_2395406
 
 /* ----------------------------------------------------
+ * Errata Workaround for Cortex A78 Errata 2742426.
+ * This applies to revisions r0p0, r1p0, r1p1 and r1p2.
+ * It is still open.
+ * x0: variant[4:7] and revision[0:3] of current cpu.
+ * Shall clobber: x0-x1, x17
+ * ----------------------------------------------------
+ */
+func errata_a78_2742426_wa
+	/* Check revision. */
+	mov	x17, x30
+	bl	check_errata_2742426
+	cbz	x0, 1f
+
+	/* Apply the workaround */
+	mrs	x1, CORTEX_A78_ACTLR5_EL1
+	bic	x1, x1, #BIT(56)
+	orr	x1, x1, #BIT(55)
+	msr	CORTEX_A78_ACTLR5_EL1, x1
+
+1:
+	ret	x17
+endfunc errata_a78_2742426_wa
+
+func check_errata_2742426
+	/* Applies to r0p0, r1p0, r1p1, r1p2 */
+	mov	x1, #CPU_REV(1, 2)
+	b	cpu_rev_var_ls
+endfunc check_errata_2742426
+
+/* ----------------------------------------------------
  * Errata Workaround for Cortex-A78 Errata 2772019
  * This applies to revisions <= r1p2 and is still open.
  * x0: variant[4:7] and revision[0:3] of current cpu.
@@ -443,6 +473,11 @@
 	bl	errata_a78_2395406_wa
 #endif
 
+#if ERRATA_A78_2742426
+	mov	x0, x18
+	bl	errata_a78_2742426_wa
+#endif
+
 #if ERRATA_A78_2779479
 	mov	x0, x18
 	bl	errata_a78_2779479_wa
@@ -526,6 +561,7 @@
 	report_errata ERRATA_A78_2242635, cortex_a78, 2242635
 	report_errata ERRATA_A78_2376745, cortex_a78, 2376745
 	report_errata ERRATA_A78_2395406, cortex_a78, 2395406
+	report_errata ERRATA_A78_2742426, cortex_a78, 2742426
 	report_errata ERRATA_A78_2772019, cortex_a78, 2772019
 	report_errata ERRATA_A78_2779479, cortex_a78, 2779479
 	report_errata WORKAROUND_CVE_2022_23960, cortex_a78, cve_2022_23960
diff --git a/lib/cpus/cpu-ops.mk b/lib/cpus/cpu-ops.mk
index 4582f28..112d8cb 100644
--- a/lib/cpus/cpu-ops.mk
+++ b/lib/cpus/cpu-ops.mk
@@ -357,6 +357,11 @@
 # to revisions r0p0, r1p0, r1p1, and r1p2 of the A78 cpu. It is still open.
 ERRATA_A78_2395406	?=0
 
+# Flag to apply erratum 2742426 workaround during reset. This erratum
+# applies to revisions r0p0, r1p0, r1p1 and r1p2 of the A78 cpu. It is still
+# open.
+ERRATA_A78_2742426	?=0
+
 # Flag to apply erratum 2772019 workaround during powerdown. This erratum
 # applies to revisions r0p0, r1p0, r1p1 and r1p2 of the A78 cpu. It is still
 # open.
@@ -1044,6 +1049,10 @@
 $(eval $(call assert_boolean,ERRATA_A78_2395406))
 $(eval $(call add_define,ERRATA_A78_2395406))
 
+# Process ERRATA_A78_2742426 flag
+$(eval $(call assert_boolean,ERRATA_A78_2742426))
+$(eval $(call add_define,ERRATA_A78_2742426))
+
 # Process ERRATA_A78_2772019 flag
 $(eval $(call assert_boolean,ERRATA_A78_2772019))
 $(eval $(call add_define,ERRATA_A78_2772019))