diff --git a/packages/tui/src/terminal.ts b/packages/tui/src/terminal.ts
index d5204fe9c..d420e41bf 100644
--- a/packages/tui/src/terminal.ts
+++ b/packages/tui/src/terminal.ts
@@ -717,10 +717,17 @@ export class ProcessTerminal implements Terminal {
 		// stderr-guard in pi-utils (mirrors openai/codex#24459).
 		suppressTerminalStderr();
 
-		// Save previous state and enable raw mode
+		// A multiplexer or SSH disconnect can leave isTTY true after its pty has
+		// been revoked. Raw mode is then impossible, so take the normal terminal
+		// disconnect path rather than letting Bun abort startup with EIO.
 		this.#wasRaw = process.stdin.isRaw || false;
 		if (process.stdin.setRawMode) {
-			process.stdin.setRawMode(true);
+			try {
+				process.stdin.setRawMode(true);
+			} catch (err) {
+				this.#markTerminalDisconnected("stdin raw mode setup failed", err);
+				return;
+			}
 		}
 		process.stdin.setEncoding("utf8");
 		process.stdin.on("end", this.#stdinEndHandler);
diff --git a/packages/tui/test/terminal-disconnect-raw-mode-throw.test.ts b/packages/tui/test/terminal-disconnect-raw-mode-throw.test.ts
index 1f1ae01da..ef10eedf9 100644
--- a/packages/tui/test/terminal-disconnect-raw-mode-throw.test.ts
+++ b/packages/tui/test/terminal-disconnect-raw-mode-throw.test.ts
@@ -76,6 +76,25 @@ describe("ProcessTerminal disconnect with a revoked pty", () => {
 		expect(signals).toContain("SIGHUP");
 	});
 
+	it("treats an initial EIO enabling raw mode as a terminal disconnect", () => {
+		Object.defineProperty(process.stdin, "setRawMode", {
+			value: () => {
+				throw new Error("setRawMode failed with errno: 5");
+			},
+			configurable: true,
+		});
+
+		const terminal = new ProcessTerminal();
+		expect(() =>
+			terminal.start(
+				() => {},
+				() => {},
+				() => terminal.stop(),
+			),
+		).not.toThrow();
+		expect(signals).toContain("SIGHUP");
+	});
+
 	it("propagates a raw-mode restore failure while the terminal is still live", () => {
 		let started = false;
 		Object.defineProperty(process.stdin, "setRawMode", {