diff --git a/arch/s390/boot/mem_detect.c b/arch/s390/boot/mem_detect.c
index 42b0cd23f04a..3becf6bbe4c7 100644
--- a/arch/s390/boot/mem_detect.c
+++ b/arch/s390/boot/mem_detect.c
@@ -184,8 +184,13 @@ void detect_memory(void)
 		return;
 	}
 
+	if (max_physmem_end) {
+		add_mem_detect_block(0, max_physmem_end);
+		mem_detect.info_source = MEM_DETECT_SCLP_READ_INFO;
+		return;
+	}
+
 	scan_memory(rzm);
 	mem_detect.info_source = MEM_DETECT_TPROT_LOOP;
-	if (!max_physmem_end)
-		max_physmem_end = get_mem_detect_end();
+	max_physmem_end = get_mem_detect_end();
 }
diff --git a/arch/s390/include/asm/mem_detect.h b/arch/s390/include/asm/mem_detect.h
index 6047a28656f5..153c3542fa8a 100644
--- a/arch/s390/include/asm/mem_detect.h
+++ b/arch/s390/include/asm/mem_detect.h
@@ -8,6 +8,7 @@ enum mem_info_source {
 	MEM_DETECT_NONE = 0,
 	MEM_DETECT_SCLP_STOR_INFO,
 	MEM_DETECT_DIAG260,
+	MEM_DETECT_SCLP_READ_INFO,
 	MEM_DETECT_TPROT_LOOP
 };