diff --git a/package.json b/package.json
index ba02a83..6b4484d 100644
--- a/package.json
+++ b/package.json
@@ -61,6 +61,7 @@
   },
   "scripts": {
     "start": "node start.js",
+    "setup": "node scripts/setup.js",
     "addbot": "node addbot.js",
     "test": "cross-env FORCE_COLOR=true supertape --no-check-assertions-count --format tap test/test.js | tap-dot",
     "test-slow": "cross-env FORCE_COLOR=true supertape --no-check-assertions-count --format tap --no-worker test/test.js -- --slow | tap-dot",
diff --git a/readme.md b/readme.md
index 992d0de..daebb1e 100644
--- a/readme.md
+++ b/readme.md
@@ -81,9 +81,9 @@ Follow these steps:
 
 1. Install dependencies: `npm install`
 
-1. Run `node scripts/seed.js` to check your setup and set the bot's initial state. It will prompt you for information. You only need to run this once ever.
+1. Run `npm run setup` to check your setup and set the bot's initial state. It will prompt you for information. You only need to run this once ever.
 
-1. Start the bridge: `npm start`
+1. Start the bridge: `npm run start`
 
 1. Add the bot to a server - use any *one* of the following commands for an invite link:
 	* (in the REPL) `addbot`
@@ -152,8 +152,8 @@ To get into the rooms on your Matrix account, use the `/invite [your mxid here]`
         │   └── *.js
         * Various files you can run once if you need them.
         └── scripts
-            * First time running a new bridge? Run this file to plant a seed, which will flourish into state for the bridge:
-            ├── seed.js
+            * First time running a new bridge? Run this file to set up prerequisites on the Matrix server:
+            ├── setup.js
             * Hopefully you won't need the rest of these. Code quality varies wildly.
             └── *.js
 
diff --git a/scripts/seed.js b/scripts/setup.js
old mode 100755
new mode 100644
similarity index 99%
rename from scripts/seed.js
rename to scripts/setup.js
index f20afb7..2fb2dd0
--- a/scripts/seed.js
+++ b/scripts/setup.js
@@ -305,7 +305,7 @@ async function validateHomeserverOrigin(serverUrlPrompt, url) {
 		}
 		// Otherwise, it's the user's problem
 		if (!guild) {
-			return die(`Error: The bot needs to upload some emojis. Please say where to upload them to. Run seed.js again with --emoji-guild=GUILD_ID`)
+			return die(`Error: The bot needs to upload some emojis. Please say where to upload them to. Run setup again with --emoji-guild=GUILD_ID`)
 		}
 		// Upload those emojis to the chosen location
 		db.prepare("REPLACE INTO auto_emoji (name, emoji_id, guild_id) VALUES ('_', '_', ?)").run(guild.id)
diff --git a/src/matrix/mreq.js b/src/matrix/mreq.js
index 4707ae6..cdcf405 100644
--- a/src/matrix/mreq.js
+++ b/src/matrix/mreq.js
@@ -5,7 +5,7 @@ const mixin = require("@cloudrac3r/mixin-deep")
 const stream = require("stream")
 const getStream = require("get-stream")
 
-const {reg} = require("./read-registration.js")
+const {reg, writeRegistration} = require("./read-registration.js")
 
 const baseUrl = `${reg.ooye.server_origin}/_matrix`
 
@@ -45,13 +45,15 @@ async function mreq(method, url, body, extra = {}) {
 	const root = await res.json()
 
 	if (!res.ok || root.errcode) {
-		if (root.error?.includes("Content-Length")) {
-			console.error(`OOYE cannot stream uploads to Synapse. Please choose one of these workarounds:`
-				+ `\n  * Run an nginx reverse proxy to Synapse, and point registration.yaml's`
-				+ `\n    \`server_origin\` to nginx`
-				+ `\n  * Set \`content_length_workaround: true\` in registration.yaml (this will`
-				+ `\n    halve the speed of bridging d->m files)`)
-			throw new Error("Synapse is not accepting stream uploads, see the message above.")
+		if (root.error?.includes("Content-Length") || !reg.ooye.content_length_workaround) {
+			reg.ooye.content_length_workaround = true
+			const root = await mreq(method, url, body, extra)
+			console.error("OOYE cannot stream uploads to Synapse. The `content_length_workaround` option"
+				+ "\nhas been activated in registration.yaml, which works around the problem, but"
+				+ "\nhalves the speed of bridging d->m files. A better way to resolve this problem"
+				+ "\nis to run an nginx reverse proxy to Synapse and re-run OOYE setup.")
+			writeRegistration(reg)
+			return root
 		}
 		delete opts.headers.Authorization
 		throw new MatrixServerError(root, {baseUrl, url, ...opts})