diff -up gnupg-2.1.21/g10/keygen.c.large-rsa gnupg-2.1.21/g10/keygen.c
--- gnupg-2.1.21/g10/keygen.c.large-rsa	2017-05-15 14:13:22.000000000 +0200
+++ gnupg-2.1.21/g10/keygen.c	2017-07-18 16:12:37.738895016 +0200
@@ -2091,7 +2091,7 @@ get_keysize_range (int algo, unsigned in
 
     default:
       *min = opt.compliance == CO_DE_VS ? 2048: 1024;
-      *max = 4096;
+      *max = opt.flags.large_rsa == 1 ? 8192 : 4096;
       def = 2048;
       break;
     }