diff --git a/testing/client/client.go b/testing/client/client.go
index 3ebd1a2..9c0ac8f 100644
--- a/testing/client/client.go
+++ b/testing/client/client.go
@@ -16,6 +16,7 @@
 package client
 
 import (
+	"fmt"
 	"testing"
 
 	"github.com/google/go-sev-guest/client"
@@ -75,18 +76,26 @@ func GetSevGuest(tcs []test.TestCase, opts *test.DeviceOptions, tb testing.TB) (
 	if err != nil {
 		tb.Fatalf("Failed to open SEV guest device: %v", err)
 	}
+	kdsImpl := test.GetKDS(tb)
+
 	badSnpRoot := make(map[string][]*trust.AMDRootCerts)
 	for product, rootCerts := range trust.DefaultRootCerts {
+		// Supplement the defaults with the missing x509 certificates.
+		pc, err := trust.GetProductChain(product, kdsImpl)
+		if err != nil {
+			tb.Fatalf("failed to get product chain for %q: %v", product, err)
+		}
+		fmt.Printf("Making bad root %s %v", product, rootCerts)
 		// By flipping the ASK and ARK, we ensure that the attestation will never verify.
 		badSnpRoot[product] = []*trust.AMDRootCerts{{
 			Product: product,
 			ProductCerts: &trust.ProductCerts{
-				Ark: rootCerts.ProductCerts.Ask,
-				Ask: rootCerts.ProductCerts.Ark,
+				Ark: pc.Ask,
+				Ask: pc.Ark,
 			},
 			AskSev: rootCerts.ArkSev,
 			ArkSev: rootCerts.AskSev,
 		}}
 	}
-	return client, nil, badSnpRoot, test.GetKDS(tb)
+	return client, nil, badSnpRoot, kdsImpl
 }
diff --git a/verify/verify.go b/verify/verify.go
index da7d36d..d4bf274 100644
--- a/verify/verify.go
+++ b/verify/verify.go
@@ -28,6 +28,7 @@ import (
 	cpb "github.com/google/go-sev-guest/proto/check"
 	spb "github.com/google/go-sev-guest/proto/sevsnp"
 	"github.com/google/go-sev-guest/verify/trust"
+	"github.com/google/logger"
 	"github.com/pborman/uuid"
 	"github.com/pkg/errors"
 	"go.uber.org/multierr"
@@ -380,7 +381,7 @@ func validateVcekCertificateProductSpecifics(r *trust.AMDRootCerts, cert *x509.C
 	if err := ValidateVcekCertIssuer(r, cert.Issuer); err != nil {
 		return err
 	}
-	if err := cert.CheckSignatureFrom(r.ProductCerts.Ask); err != nil {
+	if _, err := cert.Verify(*r.X509Options()); err != nil {
 		return fmt.Errorf("error verifying VCEK certificate: %v (%v)", err, r.ProductCerts.Ask.IsCA)
 	}
 	// VCEK is not expected to have a CRL link.
@@ -402,6 +403,7 @@ func VcekDER(vcek []byte, ask []byte, ark []byte, options *Options) (*x509.Certi
 	roots := options.TrustedRoots
 	product := vcekProductMap[exts.ProductName]
 	if len(roots) == 0 {
+		logger.Warning("Using embedded AMD certificates for SEV-SNP attestation root of trust")
 		root := &trust.AMDRootCerts{
 			Product: product,
 			// Require that the root matches embedded root certs.
@@ -512,6 +514,9 @@ func RootOfTrustToOptions(rot *cpb.RootOfTrust) (*Options, error) {
 // SnpAttestation verifies the protobuf representation of an attestation report's signature based
 // on the report's SignatureAlgo, provided the certificate chain is valid.
 func SnpAttestation(attestation *spb.Attestation, options *Options) error {
+	if options == nil {
+		return fmt.Errorf("options cannot be nil")
+	}
 	// Make sure we have the whole certificate chain if we're allowed.
 	if !options.DisableCertFetching {
 		if err := fillInAttestation(attestation, options.Getter); err != nil {