Idea

[miniexploit]

As soon as the device is disconnected client will be NULL so before sending a file or a command, we just need to check if client is NULL or not. if client == NULL we will proceed reconnect, so i think sendFile() will be something like this:

int DFUDevice::sendFile(const char* filename) {
    if(!(this -> client)) {
        this -> freeDevice();
        usleep(500000);
        if (this -> openConnection(5) != 0) {
            printf("error connecting to device, stopping here\n");
            return 2;
        }
        usleep(500000);
        this -> setAllDeviceInfo();
        usleep(500000);
    }
    usleep(500000);
    irecv_error_t stat = irecv_send_file(this -> client, filename, 1);
    usleep(500000);
    /* for some reason it returns USB upload error even though it uploads
      the file just fine, so we're only worried about IRECV_E_UNABLE_TO_CONNECT here */
    if (stat == IRECV_E_SUCCESS) {
        return 0;
    } else if (stat == IRECV_E_USB_UPLOAD) {
        if (strcmp(filename, "/dev/null") == 0) return 0;
        else return 2;
    }
    return 1;
}

i'll open a PR if you agree

[rA9stuff]

I think I already handle this with the withReconnect parameter of the sendFile method. The only time device gets nulled is after uploading iBSS and iBEC, which the main viewcontroller already assumes by calling the sendFile method with the bool parameter set to true.