diff --git a/src/soc/amd/stoneyridge/Kconfig b/src/soc/amd/stoneyridge/Kconfig
index f57111d..1e35d76 100644
--- a/src/soc/amd/stoneyridge/Kconfig
+++ b/src/soc/amd/stoneyridge/Kconfig
@@ -268,7 +268,7 @@
 
 config ACPI_CPU_STRING
 	string
-	default "P%03d"
+	default "P%03X"
 
 config ACPI_SSDT_PSD_INDEPENDENT
 	default n