diff --git a/.circleci/config.yml b/.circleci/config.yml
index 95de63a4..bb5b3a50 100644
--- a/.circleci/config.yml
+++ b/.circleci/config.yml
@@ -31,14 +31,14 @@ jobs:
                     .circleci/create-hash.sh
             - restore_cache:
                 keys:
-                    - riscv-tools-installed-v2-{{ checksum "../riscv-tools.hash" }}
+                    - riscv-tools-installed-v3-{{ checksum "../riscv-tools.hash" }}
             - run:
                 name: Building riscv-tools toolchain
                 command: |
                     .circleci/build-toolchains.sh riscv-tools
                 no_output_timeout: 120m
             - save_cache:
-                key: riscv-tools-installed-v2-{{ checksum "../riscv-tools.hash" }}
+                key: riscv-tools-installed-v3-{{ checksum "../riscv-tools.hash" }}
                 paths:
                     - "/home/riscvuser/riscv-tools-install"
     install-esp-toolchain:
@@ -55,14 +55,14 @@ jobs:
                     .circleci/create-hash.sh
             - restore_cache:
                 keys:
-                    - esp-tools-installed-v2-{{ checksum "../esp-tools.hash" }}
+                    - esp-tools-installed-v3-{{ checksum "../esp-tools.hash" }}
             - run:
                 name: Building esp-tools toolchain
                 command: |
                     .circleci/build-toolchains.sh esp-tools
                 no_output_timeout: 120m
             - save_cache:
-                key: esp-tools-installed-v2-{{ checksum "../esp-tools.hash" }}
+                key: esp-tools-installed-v3-{{ checksum "../esp-tools.hash" }}
                 paths:
                     - "/home/riscvuser/esp-tools-install"
     install-verilator:
@@ -105,7 +105,7 @@ jobs:
                     .circleci/create-hash.sh
             - restore_cache:
                 keys:
-                    - riscv-tools-installed-v2-{{ checksum "../riscv-tools.hash" }}
+                    - riscv-tools-installed-v3-{{ checksum "../riscv-tools.hash" }}
             - run:
                 name: Build extra tests
                 command: .circleci/build-extra-tests.sh
@@ -131,7 +131,7 @@ jobs:
                     .circleci/create-hash.sh
             - restore_cache:
                 keys:
-                    - riscv-tools-installed-v2-{{ checksum "../riscv-tools.hash" }}
+                    - riscv-tools-installed-v3-{{ checksum "../riscv-tools.hash" }}
             - restore_cache:
                 keys:
                     - verilator-installed-v3-{{ checksum "sims/verilator/verilator.mk" }}
@@ -160,7 +160,7 @@ jobs:
                     .circleci/create-hash.sh
             - restore_cache:
                 keys:
-                    - riscv-tools-installed-v2-{{ checksum "../riscv-tools.hash" }}
+                    - riscv-tools-installed-v3-{{ checksum "../riscv-tools.hash" }}
             - restore_cache:
                 keys:
                     - verilator-installed-v3-{{ checksum "sims/verilator/verilator.mk" }}
@@ -189,7 +189,7 @@ jobs:
                     .circleci/create-hash.sh
             - restore_cache:
                 keys:
-                    - riscv-tools-installed-v2-{{ checksum "../riscv-tools.hash" }}
+                    - riscv-tools-installed-v3-{{ checksum "../riscv-tools.hash" }}
             - restore_cache:
                 keys:
                     - verilator-installed-v3-{{ checksum "sims/verilator/verilator.mk" }}
@@ -218,7 +218,7 @@ jobs:
                     .circleci/create-hash.sh
             - restore_cache:
                 keys:
-                    - riscv-tools-installed-v2-{{ checksum "../riscv-tools.hash" }}
+                    - riscv-tools-installed-v3-{{ checksum "../riscv-tools.hash" }}
             - restore_cache:
                 keys:
                     - verilator-installed-v3-{{ checksum "sims/verilator/verilator.mk" }}
@@ -247,7 +247,7 @@ jobs:
                     .circleci/create-hash.sh
             - restore_cache:
                 keys:
-                    - riscv-tools-installed-v2-{{ checksum "../riscv-tools.hash" }}
+                    - riscv-tools-installed-v3-{{ checksum "../riscv-tools.hash" }}
             - restore_cache:
                 keys:
                     - verilator-installed-v3-{{ checksum "sims/verilator/verilator.mk" }}
@@ -276,7 +276,7 @@ jobs:
                     .circleci/create-hash.sh
             - restore_cache:
                 keys:
-                    - esp-tools-installed-v2-{{ checksum "../esp-tools.hash" }}
+                    - esp-tools-installed-v3-{{ checksum "../esp-tools.hash" }}
             - restore_cache:
                 keys:
                     - verilator-installed-v3-{{ checksum "sims/verilator/verilator.mk" }}
@@ -305,7 +305,7 @@ jobs:
                     .circleci/create-hash.sh
             - restore_cache:
                 keys:
-                    - riscv-tools-installed-v2-{{ checksum "../riscv-tools.hash" }}
+                    - riscv-tools-installed-v3-{{ checksum "../riscv-tools.hash" }}
             - restore_cache:
                 keys:
                     - verilator-installed-v3-{{ checksum "sims/verilator/verilator.mk" }}
@@ -334,7 +334,7 @@ jobs:
                     .circleci/create-hash.sh
             - restore_cache:
                 keys:
-                    - riscv-tools-installed-v2-{{ checksum "../riscv-tools.hash" }}
+                    - riscv-tools-installed-v3-{{ checksum "../riscv-tools.hash" }}
             - restore_cache:
                 keys:
                     - verilator-installed-v3-{{ checksum "sims/verilator/verilator.mk" }}
@@ -363,7 +363,7 @@ jobs:
                     .circleci/create-hash.sh
             - restore_cache:
                 keys:
-                    - riscv-tools-installed-v2-{{ checksum "../riscv-tools.hash" }}
+                    - riscv-tools-installed-v3-{{ checksum "../riscv-tools.hash" }}
             - restore_cache:
                 keys:
                     - verilator-installed-v3-{{ checksum "sims/verilator/verilator.mk" }}
@@ -389,7 +389,7 @@ jobs:
                     .circleci/create-hash.sh
             - restore_cache:
                 keys:
-                    - riscv-tools-installed-v2-{{ checksum "../riscv-tools.hash" }}
+                    - riscv-tools-installed-v3-{{ checksum "../riscv-tools.hash" }}
             - restore_cache:
                 keys:
                     - verilator-installed-v3-{{ checksum "sims/verilator/verilator.mk" }}
@@ -410,7 +410,7 @@ jobs:
                     .circleci/create-hash.sh
             - restore_cache:
                 keys:
-                    - riscv-tools-installed-v2-{{ checksum "../riscv-tools.hash" }}
+                    - riscv-tools-installed-v3-{{ checksum "../riscv-tools.hash" }}
             - restore_cache:
                 keys:
                     - example-{{ .Branch }}-{{ .Revision }}
@@ -434,7 +434,7 @@ jobs:
                     .circleci/create-hash.sh
             - restore_cache:
                 keys:
-                    - riscv-tools-installed-v2-{{ checksum "../riscv-tools.hash" }}
+                    - riscv-tools-installed-v3-{{ checksum "../riscv-tools.hash" }}
             - restore_cache:
                 keys:
                     - boomrocketexample-{{ .Branch }}-{{ .Revision }}
@@ -458,7 +458,7 @@ jobs:
                     .circleci/create-hash.sh
             - restore_cache:
                 keys:
-                    - riscv-tools-installed-v2-{{ checksum "../riscv-tools.hash" }}
+                    - riscv-tools-installed-v3-{{ checksum "../riscv-tools.hash" }}
             - restore_cache:
                 keys:
                     - boom-{{ .Branch }}-{{ .Revision }}
@@ -482,7 +482,7 @@ jobs:
                     .circleci/create-hash.sh
             - restore_cache:
                 keys:
-                    - riscv-tools-installed-v2-{{ checksum "../riscv-tools.hash" }}
+                    - riscv-tools-installed-v3-{{ checksum "../riscv-tools.hash" }}
             - restore_cache:
                 keys:
                     - rocketchip-{{ .Branch }}-{{ .Revision }}
@@ -506,7 +506,7 @@ jobs:
                     .circleci/create-hash.sh
             - restore_cache:
                 keys:
-                    - esp-tools-installed-v2-{{ checksum "../esp-tools.hash" }}
+                    - esp-tools-installed-v3-{{ checksum "../esp-tools.hash" }}
             - restore_cache:
                 keys:
                     - hwacha-{{ .Branch }}-{{ .Revision }}
@@ -530,7 +530,7 @@ jobs:
                     .circleci/create-hash.sh
             - restore_cache:
                 keys:
-                    - riscv-tools-installed-v2-{{ checksum "../riscv-tools.hash" }}
+                    - riscv-tools-installed-v3-{{ checksum "../riscv-tools.hash" }}
             - restore_cache:
                 keys:
                     - tracegen-{{ .Branch }}-{{ .Revision }}
@@ -554,7 +554,7 @@ jobs:
                     .circleci/create-hash.sh
             - restore_cache:
                 keys:
-                    - riscv-tools-installed-v2-{{ checksum "../riscv-tools.hash" }}
+                    - riscv-tools-installed-v3-{{ checksum "../riscv-tools.hash" }}
             - restore_cache:
                 keys:
                     - firesim-{{ .Branch }}-{{ .Revision }}
@@ -581,7 +581,7 @@ jobs:
                     .circleci/create-hash.sh
             - restore_cache:
                 keys:
-                    - riscv-tools-installed-v2-{{ checksum "../riscv-tools.hash" }}
+                    - riscv-tools-installed-v3-{{ checksum "../riscv-tools.hash" }}
             - restore_cache:
                 keys:
                     - fireboom-{{ .Branch }}-{{ .Revision }}
diff --git a/scripts/build-toolchains.sh b/scripts/build-toolchains.sh
index 9d7b3deb..e858e452 100755
--- a/scripts/build-toolchains.sh
+++ b/scripts/build-toolchains.sh
@@ -10,10 +10,17 @@ RDIR=$(pwd)
 CHIPYARD_DIR="${CHIPYARD_DIR:-$(git rev-parse --show-toplevel)}"
 
 usage() {
-    echo "usage: ${0} [riscv-tools | esp-tools | ec2fast]"
+    echo "usage: ${0} [OPTIONS] [riscv-tools | esp-tools | ec2fast]"
+    echo ""
+    echo "Installation Types"
     echo "   riscv-tools: if set, builds the riscv toolchain (this is also the default)"
     echo "   esp-tools: if set, builds esp-tools toolchain used for the hwacha vector accelerator"
     echo "   ec2fast: if set, pulls in a pre-compiled RISC-V toolchain for an EC2 manager instance"
+    echo ""
+    echo "Options"
+    echo "   --prefix PREFIX : Install destination. If unset, defaults to $(pwd)/riscv-tools-install"
+    echo "                     or $(pwd)/esp-tools-install"
+    echo "   --help -h       : Display this message"
     exit "$1"
 }
 
@@ -27,38 +34,34 @@ die() {
 
 TOOLCHAIN="riscv-tools"
 EC2FASTINSTALL="false"
+RISCV=""
 
-while getopts 'hH-:' opt ; do
-    case $opt in
-    h|H)
-        usage 3 ;;
-    -)
-        case $OPTARG in
-        help)
+# getopts does not support long options, and is inflexible
+while [ "$1" != "" ];
+do
+    case $1 in
+        -h | --help | help )
             usage 3 ;;
-        ec2fast) # Preserve compatibility
-            EC2FASTINSTALL=true ;;
-        *)
-            error "invalid option: --${OPTARG}"
+        -p | --prefix )
+            shift
+            RISCV=$(realpath $1) ;;
+        riscv-tools | esp-tools)
+            TOOLCHAIN=$1 ;;
+        ec2fast )
+            EC2FASTINSTALL="true" ;;
+        * )
+            error "invalid option $1"
             usage 1 ;;
-        esac ;;
-    *)
-        error "invalid option: -${opt}"
-        usage 1 ;;
     esac
+    shift
 done
 
-shift $((OPTIND - 1))
-
-if [ "$1" = ec2fast ] ; then
-    EC2FASTINSTALL=true
-elif [ -n "$1" ] ; then
-    TOOLCHAIN="$1"
+if [ -z "$RISCV" ] ; then
+      INSTALL_DIR="$TOOLCHAIN-install"
+      RISCV="$(pwd)/$INSTALL_DIR"
 fi
 
-INSTALL_DIR="$TOOLCHAIN-install"
-
-RISCV="$(pwd)/$INSTALL_DIR"
+echo "Installing toolchain to $RISCV"
 
 # install risc-v tools
 export RISCV="$RISCV"