diff --git a/security/certverifier/NSSCertDBTrustDomain.cpp b/security/certverifier/NSSCertDBTrustDomain.cpp
--- a/security/certverifier/NSSCertDBTrustDomain.cpp
+++ b/security/certverifier/NSSCertDBTrustDomain.cpp
@@ -1057,22 +1057,20 @@ InitializeNSS(const nsACString& dir, boo
   // "/usr/lib/nss/libnssckbi.so".
   uint32_t flags = NSS_INIT_NOROOTINIT | NSS_INIT_OPTIMIZESPACE;
   if (readOnly) {
     flags |= NSS_INIT_READONLY;
   }
   if (!loadPKCS11Modules) {
     flags |= NSS_INIT_NOMODDB;
   }
-  nsAutoCString dbTypeAndDirectory("sql:");
-  dbTypeAndDirectory.Append(dir);
   MOZ_LOG(gCertVerifierLog, LogLevel::Debug,
-          ("InitializeNSS(%s, %d, %d)", dbTypeAndDirectory.get(), readOnly,
+          ("InitializeNSS(%s, %d, %d)", PromiseFlatCString(dir).get(), readOnly,
            loadPKCS11Modules));
-  SECStatus srv = NSS_Initialize(dbTypeAndDirectory.get(), "", "",
+  SECStatus srv = NSS_Initialize(PromiseFlatCString(dir).get(), "", "",
                                  SECMOD_DB, flags);
   if (srv != SECSuccess) {
     return srv;
   }
 
   if (!readOnly) {
     UniquePK11SlotInfo slot(PK11_GetInternalKeySlot());
     if (!slot) {