diff --git a/README.md b/README.md
index 379b76c..d2ec1cb 100644
--- a/README.md
+++ b/README.md
@@ -520,6 +520,10 @@ CPU.
 The following commands will build the RISC-V gnu toolchain and libraries for a
 pure RV32I target, and install it in `/opt/riscv32i`:
 
+    # Ubuntu packages needed:
+    sudo apt-get install autoconf automake autotools-dev curl libmpc-dev libmpfr-dev \
+            libgmp-dev gawk build-essential bison flex texinfo gperf
+
     sudo mkdir /opt/riscv32i
     sudo chown $USER /opt/riscv32i