diff --git a/contrib/devtools/chainparams/README.md b/contrib/devtools/chainparams/README.md
index eba13f6560..b0766360f7 100644
--- a/contrib/devtools/chainparams/README.md
+++ b/contrib/devtools/chainparams/README.md
@@ -1,32 +1,32 @@
 # Chainparams Constants
 
 Utilities to generate chainparams constants that are compiled into the client
 (see [src/chainparamsconstants.h](/src/chainparamsconstants.h).
 
 The chainparams constants are fetched from bitcoind, dumped to intermediate
 files, and then compiled into [src/chainparamsconstants.h](/src/chainparamsconstants.h).
 If you're running bitcoind locally, the following instructions will work
 out-of-the-box:
 
 ## Mainnet
 ```
 bitcoind
 make_chainparams > chainparams_main.txt
 ```
 
 ## Testnet
 ```
 bitcoind --testnet
-make_chainparams --testnet -a 127.0.0.1:18332 > chainparams_test.txt
+make_chainparams -a 127.0.0.1:18332 > chainparams_test.txt
 ```
 
 ## Build C++ Header File
 ```
 generate_chainparams_constants.py . > ../../../src/chainparamsconstants.h
 ```
 
 ## Testing
 
 Updating these constants should be reviewed carefully, with a
 reindex-chainstate, checkpoints=0, and assumevalid=0 to catch any defect that
 causes rejection of blocks in the past history.