[Bug]: Flasher fails to connect to Heltec V4. Works fine for V3

[roberthadow]

Category

Serial

Hardware

Heltec V3, Other

Is this bug report about any UI component firmware like InkHUD or Meshtatic UI (MUI)?

• Meshtastic UI aka MUI colorTFT
• InkHUD ePaper
• OLED slide UI on any display

Firmware Version

2.7.13

Description

The flasher works fine for Heltec V3.2. The serial port dropdown menu provides the following choice:
"CP2102 USB to UART Bridge Controller (ttyUSB1) - Paired..." Flashing is unremarkable and reliable.

With Heltec V4, the serial port dropdown menu provides a fully enumerated description of the Heltec V4--so long that the specific USB port is not visible. "heltec_wifi_lora_32 V4 (16 MB FLASH 2 MB PSRAM) ttyA..."

At the command to connect, the result in the terminal is : "Error. Failed to connect to device."

A second try at "Erase Flash and Install" results in:
"InvalidStateError: Failed to execute 'open' on 'SerialPort': The port is already open.

Disconnecting and reconnecting USB doesn't change anything.

Another try with the Reboot button held while plugging USB results in failure to connect.

Another try with the Prog button held while plugging USB results in:
"NetworkError: Failed to execute 'open' on 'SerialPort': Failed to open serial port.

Then I tried --factory reset. The first time didn't stick, but the second time gave me a clean configuration with firmware V2.7.11. Same failure to connect.

I'm using Ubuntu 24.04.3 LTS with Chrome Version 140.0.7339.127 (Official Build) (64-bit)

Help me please with this--How do I discover the flasher version I am using? I don't want to complain about an old version. The one I am using is whatever popped into my browser today.

Relevant log output

[cravey]

The v4 has a different USB interface, so the process to get it into the right mode for flashing is different. It has to be specifically rebooted into the right mode. I've got one. It took me several hours to figure this out and I've seen the question at least four other times on discords, Reddit, etc.

The reason it worked the first time is that without an installed firmware from the factory, it defaults to the correct mode. So you get one flash on a new device, then have to jump through this hoop every time after that.

1. Disconnect from all power sources including USB.
2. Hold down the boot button
3. Connect to USB while holding down the boot button (screen typically stays off)
4. Release boot button
5. You'll see the new device in the flasher selection dialog
6. Flash the v4.

This isn't a Meshtastic bug, it's just another questionable design decision by Heltec like the power connectors that point the wrong direction so normal cases don't work.

73

[CollinChidiac]

I'm in the same boat.

I was able to flash the V3 software on the V4 hardware, but when trying to flash the V4 software on the v4 hardware it doesn't work.

I followed the instructions from cravey but I am still left in the position where DFU connection shows as failed.

Even if I manually select v4 as the device, the flash button still appears greyed out.

Once again if I go through the process as if it were a v3, it works perfectly fine.

[cravey]

@CollinChidiac are you trying to flash 2.7.13 or something else?

[CollinChidiac]

@CollinChidiac are you trying to flash 2.7.13 or something else?

2.6.11

{EDIT}...which now I see doesnt work but the 2.7.13 is available....thats my fault.

Although even with that, I just tried to get DFU to work but it still fails with 2.7.13

esptool.js
Serial port WebSerial VendorID 0x303a ProductID 0x1001
Connecting...
NetworkError: Failed to execute 'open' on 'SerialPort': Failed to open serial port.

{EDIT 2} 8th time's the charm, its erasing the flash rn

{EDIT 3} Annnd it failed, webpage froze and serial connection failed

{Final Edit} finally got it working, I wish I could say that I know what was different the 12th time around but it is working. Sorry again for the confusion on my part with having the wrong version.

[cravey]

@CollinChidiac I also had issues with the driver being weird sometimes. Rebooting my computer solved it after much annoyance. So... did you try turning it off and then back on again? Are you on windows, or *nix/mac?

[garthvh]

Support for the v4 is not in 2.6.11

[roberthadow]

@garthvh You are correct. In the flasher, if Heltec V4 and firmware V2.6.11 are selected, the flash button is disabled.

@cravey I followed your procedure: [tl;dr boot, PRG, and RST buttons]

• Disconnect battery and USB from Heltec V4.
• Open Flasher, select Heltec V4, select firmware V2.7.13, click Flash, select Full erase and install, click Erase Flash and Install
• Observe the USB drop down without Heltec selection
• Hold the RST button, plug in the USB. Observe a quick red flash. Release the RST button.
• The USB drop down populates. Select the Heltec AT THE BOTTOM OF THE LIST. Click Connect. Observe the terminal

After about twelve seconds, I see "Error. Failed to connect to device."

I tried @CollinChidiac 's method. Eight times.

• Unplug the USB.
• Click Erase Flash and Install. Observe the USB drop down without Heltec selection
• Hold the RST button, plug in the USB. Observe a quick red flash. Release the RST button.
• The USB drop down populates. Select the Heltec AT THE BOTTOM OF THE LIST. Quickly click Connect. Observe the terminal

No dice.

Then I tried holding the PRG button, instead. Viola!

So here it is, what works for me:

• Disconnect battery and USB from Heltec V4.
• Open Flasher, select Heltec V4, select firmware V2.7.13, click Flash, select Full erase and install, click Erase Flash and Install
• Observe the USB drop down without Heltec selection
• Hold the PRG button, plug in the USB. Observe a quick red flash. Release the PRG button.
• The USB drop down populates. Select USB JTAG. Click Connect. Observe the terminal and flash process
• After it says leaving, press the RST button

The USB port on the Heltec V4 appears to be less reliable, generally, than that on the V3.2. A laptop and USB cables that worked more or less reliably before suffer now. I use a bash script with CLI over USB to configure the basics, including IP address, then CLI over WiFi for the rest. I use both --timeout and sleep commands not to overwork the device.

[thebentern]

Then I tried holding the PRG button, instead. Viola!

So here it is, what works for me:

Disconnect battery and USB from Heltec V4.
Open Flasher, select Heltec V4, select firmware V2.7.13, click Flash, select Full erase and install, click Erase Flash and Install
Observe the USB drop down without Heltec selection
Hold the PRG button, plug in the USB. Observe a quick red flash. Release the PRG button.
The USB drop down populates. Select USB JTAG. Click Connect. Observe the terminal and flash process
After it says leaving, press the RST button

The USB port on the Heltec V4 appears to be less reliable, generally, than that on the V3.2. A laptop and USB cables that worked more or less reliably before suffer now. I use a bash script with CLI over USB to configure the basics, including IP address, then CLI over WiFi for the rest. I use both --timeout and sleep commands not to overwork the device.

This is the normal process for native USB ESP32-S3 devices. In the V4, they dropped the CP2102 usb to serial converter which automatically puts the esp32 into bootloader mode and went with the build in USB/JTAG mode of the ESP32-S3

[cravey]

@roberthadow prg and boot are the same thing. You just did the same thing as I said to do. 🤷‍♀️

[CollinChidiac]

@CollinChidiac I also had issues with the driver being weird sometimes. Rebooting my computer solved it after much annoyance. So... did you try turning it off and then back on again? Are you on windows, or *nix/mac?

Although that's usually my go to (the IT special lol) I just kept trying over and over again until it worked.

For others in the same position I am:

• On windows
• Battery disconnected from heltec
• Using a USB-C to USB-C cable
• Using chrome for the web flasher
• Using 2.7.13
• Pressing and holding PRG while inserting USB cable
• It might take more than a few tries to get it to work.

[clifffriedel]

Then I tried holding the PRG button, instead. Viola!
So here it is, what works for me:

Disconnect battery and USB from Heltec V4.
Open Flasher, select Heltec V4, select firmware V2.7.13, click Flash, select Full erase and install, click Erase Flash and Install
Observe the USB drop down without Heltec selection
Hold the PRG button, plug in the USB. Observe a quick red flash. Release the PRG button.
The USB drop down populates. Select USB JTAG. Click Connect. Observe the terminal and flash process
After it says leaving, press the RST button

The USB port on the Heltec V4 appears to be less reliable, generally, than that on the V3.2. A laptop and USB cables that worked more or less reliably before suffer now. I use a bash script with CLI over USB to configure the basics, including IP address, then CLI over WiFi for the rest. I use both --timeout and sleep commands not to overwork the device.

This is the normal process for native USB ESP32-S3 devices. In the V4, they dropped the CP2102 usb to serial converter which automatically puts the esp32 into bootloader mode and went with the build in USB/JTAG mode of the ESP32-S3

I was unable to get it to flash using the BOOT button. When I used the PRG button though, it worked right away. Not sure why as I thought they were both the same also, but for some reason, only PRG worked for me.