Write failed for device: errorCode: 401 attErrorCode: 128

[webjay]

Prerequisites

• I checked the documentation and FAQ without finding a solution
• I checked to make sure that this issue has not already been filed
• I'm sure that question is related to the library itself and not Bluetooth Low Energy or Classic in general. If that so, please post your question on StackOverflow.
• I'm running the latest version

Question

I have a Moko M1 based on nRF52810 which I am trying to write to.
I can write to it successfully via the "nRF Connect" app.

I know that the error 401 means "Couldn't write to specified characteristic", however isWritableWithResponse: true.
I don't know what the error attErrorCode: 128 indicates?

In both nRF Connect and via console.log I only see one service and one characteristic.

I have the content stored as a string for now, from this:
const fileContent = readFileSync('/Users/jacob/Downloads/EA140CF93E0D.zip', { encoding: 'base64' });

What might I be doing wrong?

const isConnected = await device.isConnected();
if (!isConnected) await device.connect();
await device.discoverAllServicesAndCharacteristics();
const services = await device.services();
const characteristics = await device.characteristicsForService(services[0].uuid);
await characteristics[0].writeWithResponse(fileContent).catch((error) => {
  console.log(JSON.stringify(error));
});

[webjay]

It turns out I needed to use react-native-nordic-dfu:
Pilloxa/react-native-nordic-dfu#171 (comment)