diff --git a/Jenkinsfile b/Jenkinsfile
index bf9bd438a6..50ab151509 100644
--- a/Jenkinsfile
+++ b/Jenkinsfile
@@ -142,7 +142,7 @@ def setupCredentials() {
 }
 
 
-def build_channel(String channel_name, def prebuilt) {
+def build_channel(String channel_name) {
   return parallel (
     "${channel_name} (git)": {
       deviceStage("build git", "tici-needs-can", [], [
@@ -151,7 +151,7 @@ def build_channel(String channel_name, def prebuilt) {
     },
     "${channel_name} (casync)": {
       deviceStage("build casync", "tici-needs-can", [], [
-        ["build ${channel_name}", "BUILD_DIR=/data/releasepilot OUTPUT_DIR=/data/casync RELEASE_CHANNEL=${channel_name} $SOURCE_DIR/release/build_casync_channel.sh"],
+        ["build ${channel_name}", "BUILD_DIR=/data/openpilot_build OUTPUT_DIR=/data/casync RELEASE_CHANNEL=${channel_name} $SOURCE_DIR/release/build_casync_channel.sh"],
         //["upload ${channel_name}", "RELEASE_CHANNEL=${channel_name} $SOURCE_DIR/release/upload_casync_channel.sh"],
       ])
     }
@@ -187,7 +187,7 @@ node {
     }
 
     if (env.BRANCH_NAME == 'master-ci') {
-      build_channel("nightly", true)
+      build_channel("nightly")
     }
 
     if (!env.BRANCH_NAME.matches(excludeRegex)) {
diff --git a/release/README.md b/release/README.md
new file mode 100644
index 0000000000..11c9d49c5b
--- /dev/null
+++ b/release/README.md
@@ -0,0 +1,24 @@
+# openpilot releases
+
+
+## terms
+
+`channel` - a named version of openpilot (git branches or casync caidx)<br>
+`prebuilt` - a channel prebuilt for the tici, no building required on device<br>
+`release` - a channel that is prebuilt and also has `ALLOW_DEBUG` false. (`nightly`, `release3`)<br>
+
+## creating casync channel
+
+`build_casync_channel.sh` - creates a `prebuilt` openpilot channel, ready to upload to `openpilot-channels`
+
+```bash
+# run on a tici, within the directory you want to create the release from
+# creates a prebuilt version of openpilot into BUILD_DIR and outputs the caidx
+# and other casync files into CASYNC_DIR for uploading to openpilot-channels
+BUILD_DIR=/data/openpilot_build    \
+CASYNC_DIR=/data/casync            \
+RELEASE_CHANNEL=nightly            \
+release/build_casync_channel.sh
+```
+
+`upload_casync_channel.sh` - helper for uploading a casync channel to `openpilot-channels`
diff --git a/release/build_casync_channel.sh b/release/build_casync_channel.sh
index 0d119889d7..07313082e6 100755
--- a/release/build_casync_channel.sh
+++ b/release/build_casync_channel.sh
@@ -4,13 +4,13 @@ set -ex
 
 DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" >/dev/null && pwd)"
 
-export OUTPUT_DIR="${OUTPUT_DIR:=/tmp/casync}"
+export CASYNC_DIR="${CASYNC_DIR:=/tmp/casync}"
 export SOURCE_DIR="$(git -C $DIR rev-parse --show-toplevel)"
 export BUILD_DIR="${BUILD_DIR:=$(mktemp -d)}"
 
-echo "Creating casync channel from $SOURCE_DIR to $OUTPUT_DIR"
+echo "Creating casync channel from $SOURCE_DIR to $CASYNC_DIR"
 
-mkdir -p $OUTPUT_DIR
+mkdir -p $CASYNC_DIR
 rm -rf $BUILD_DIR
 mkdir -p $BUILD_DIR
 
@@ -18,4 +18,4 @@ release/copy_release_files.sh $SOURCE_DIR $BUILD_DIR
 release/create_prebuilt.sh $BUILD_DIR
 
 cd $SOURCE_DIR
-release/create_casync_channel.py $BUILD_DIR $OUTPUT_DIR $RELEASE_CHANNEL
+release/create_casync_channel.py $BUILD_DIR $CASYNC_DIR $RELEASE_CHANNEL