fix: shorten preamble, skip empty screens

packages/serial/src/ZWaveSerialPortBase.ts

@@ -158,7 +158,9 @@ export class ZWaveSerialPortBase extends PassThrough {
 			if (this.mode == undefined) {
 				// If we haven't figured out the startup mode yet,
 				// inspect the chunk to see if it contains the bootloader preamble
-				const str = (data as Buffer).toString("ascii").trim();
+				const str = (data as Buffer).toString("ascii")
+					// like .trim(), but including null bytes
+					.replaceAll(/^[\s\0]+|[\s\0]+$/g, "");
 				this.mode = str.startsWith(bootloaderMenuPreamble)
 					? ZWaveSerialMode.Bootloader
 					: ZWaveSerialMode.SerialAPI;

packages/serial/src/parsers/BootloaderParsers.ts

@@ -79,8 +79,9 @@ export class BootloaderScreenParser extends Transform {
 			const screen = this.receiveBuffer.slice(0, nulCharIndex).trim();
 			this.receiveBuffer = this.receiveBuffer.slice(nulCharIndex + 1);
 
-			this.logger?.bootloaderScreen(screen);
+			if (screen === "") continue;
 
+			this.logger?.bootloaderScreen(screen);
 			this.push(screen);
 		}
 
@@ -107,7 +108,9 @@ export class BootloaderScreenParser extends Transform {
 	}
 }
 
-export const bootloaderMenuPreamble = "Gecko Bootloader";
+// Sometimes the first chunk of the bootloader screen is relatively short,
+// so we consider the following enough to detect the bootloader menu:
+export const bootloaderMenuPreamble = "Gecko Boo";
 const preambleRegex = /^Gecko Bootloader v(?<version>\d+\.\d+\.\d+)/;
 const menuSuffix = "BL >";
 const optionsRegex = /^(?<num>\d+)\. (?<option>.+)/gm;