Remove reg code from config blob and format config blob as json

src/cmd/setup-tachyon.js

@@ -112,27 +112,41 @@ Welcome to the Particle Tachyon setup! This interactive command:
 			);
 
 			let configBlobPath = loadConfig;
+			let configBlob = null;
 			if (configBlobPath) {
+				try {
+					const data = fs.readFileSync(configBlobPath, 'utf8');
+					configBlob = JSON.parse(data);
+					const res = await this._createConfigBlob({
+						registrationCode,
+						systemPassword: configBlob.system_password,
+						wifi: configBlob.wifi,
+						sshKey: configBlob.ssh_key
+					});
+					configBlobPath = res.path;
+				} catch (error) {
+					throw new Error(`The configuration file is not a valid JSON file: ${error.message}`);
+				}
 				this.ui.write(
 					`${os.EOL}${os.EOL}Skipping Step 6 - Using configuration file: ` + loadConfig + `${os.EOL}`
 				);
 			} else {
-				configBlobPath = await this._runStepWithTiming(
+				const res = await this._runStepWithTiming(
 					'Creating the configuration file to write to the Tachyon device...',
 					6,
 					() => this._createConfigBlob({ registrationCode, ...config })
 				);
+				configBlobPath = res.path;
+				configBlob = res.configBlob;
 			}
+
 			const xmlPath = await this._createXmlFile(configBlobPath);
 
 			if (saveConfig) {
-				this.ui.write(`${os.EOL}${os.EOL}Configuration file written here: ${saveConfig}${os.EOL}`);
-				fs.copyFileSync(configBlobPath, saveConfig);
+				fs.writeFileSync(saveConfig, JSON.stringify(configBlob, null, 2));
+				this.ui.write(`${os.EOL}Configuration file written here: ${saveConfig}${os.EOL}`);
 			}
 
-			//what files to flash?
-			// const filesToFlash = skipFlashingOs ? [xmlPath] : [packagePath, xmlPath];
-
 			const flashSuccessful = await this._runStepWithTiming(
 				`Okay—last step! We're now flashing the device with the configuration, including the password, Wi-Fi settings, and operating system.${os.EOL}` +
         `Heads up: this is a large image and will take around 10 minutes to complete. Don't worry—we'll show a progress bar as we go!${os.EOL}${os.EOL}` +
@@ -487,7 +501,7 @@ Welcome to the Particle Tachyon setup! This interactive command:
 
 		// Write config JSON to a temporary file (generate a filename with the temp npm module)
 		// prefixed by the JSON string length as a 32 bit integer
-		let jsonString = JSON.stringify(config);
+		let jsonString = JSON.stringify(config, null, 2);
 		const buffer = Buffer.alloc(4 + Buffer.byteLength(jsonString));
 		buffer.writeUInt32BE(Buffer.byteLength(jsonString), 0);
 		buffer.write(jsonString, 4);
@@ -496,7 +510,7 @@ Welcome to the Particle Tachyon setup! This interactive command:
 		fs.writeSync(tempFile.fd, buffer);
 		fs.closeSync(tempFile.fd);
 
-		return tempFile.path;
+		return { path: tempFile.path, configBlob: config };
 	}
 
 	_generateShadowCompatibleHash(password) {