diff --git a/sys/platform/pc64/acpica/acpi_sdt.c b/sys/platform/pc64/acpica/acpi_sdt.c
--- a/sys/platform/pc64/acpica/acpi_sdt.c
+++ b/sys/platform/pc64/acpica/acpi_sdt.c
@@ -128,8 +128,15 @@
 	for (i = 0; i < size - sizeof(*rsdp); i += ACPI_RSDP_SCAN_STEP) {
 		rsdp = (const ACPI_TABLE_RSDP *)&target[i];
 		if (memcmp(rsdp->Signature, ACPI_SIG_RSDP,
-			   sizeof(rsdp->Signature)) == 0)
-			return rsdp;
+			   sizeof(rsdp->Signature)) == 0) {
+			/* DF-1114: validate ACPI 1.0 checksum (first 20 bytes) */
+			uint8_t sum = 0;
+			int j;
+			for (j = 0; j < 20; j++)
+				sum += ((const uint8_t *)rsdp)[j];
+			if (sum == 0)
+				return rsdp;
+		}
 	}
 	return NULL;
 }