fix https://github.com/acmesh-official/acme.sh/issues/4535

acme.sh

@@ -2873,7 +2873,7 @@ _initpath() {
 
     if _isEccKey "$_ilength"; then
       DOMAIN_PATH="$domainhomeecc"
-    else
+    elif [ -z "$__SELECTED_RSA_KEY" ]
       if [ ! -d "$domainhome" ] && [ -d "$domainhomeecc" ]; then
         _info "The domain '$domain' seems to have a ECC cert already, lets use ecc cert."
         DOMAIN_PATH="$domainhomeecc"
@@ -7518,6 +7518,9 @@ _process() {
     --keylength | -k)
       _keylength="$2"
       shift
+      if [ "$_keylength" ] && ! _isEccKey "$_keylength"; then
+        export __SELECTED_RSA_KEY=1
+      fi
       ;;
     -ak | --accountkeylength)
       _accountkeylength="$2"