diff -up firefox-78.9.0/security/certverifier/NSSCertDBTrustDomain.cpp.slot-fail firefox-78.9.0/security/certverifier/NSSCertDBTrustDomain.cpp
--- firefox-78.9.0/security/certverifier/NSSCertDBTrustDomain.cpp.slot-fail	2021-04-08 08:02:13.879018493 +0200
+++ firefox-78.9.0/security/certverifier/NSSCertDBTrustDomain.cpp	2021-04-08 08:05:56.713623197 +0200
@@ -118,7 +118,7 @@ static Result FindRootsWithSubject(Uniqu
     CERTCertificateList* rawResults = nullptr;
     if (PK11_FindRawCertsWithSubject(rootsModule->slots[slotIndex], &subject,
                                      &rawResults) != SECSuccess) {
-      return Result::FATAL_ERROR_LIBRARY_FAILURE;
+      continue;
     }
     // rawResults == nullptr means we didn't find any matching certificates
     if (!rawResults) {