Assembled CTR2-Dial units are programmed with the latest firmware and your firmware license key is installed. If you purchased an enclosure kit your firmware license key will be written on the bottom label for the enclosure. You’ll need to download the firmware here and install it in your M5Dial. The instructions are in the operation manual included in the firmware zip file. You’ll need to enter your license key into the program the first time you use it.

Please consider joining the CTR2 group at https://groups.io/g/CTR2 so you can receive notification when I update the firmware on any of the CTR2 products.


January 30, 2025 – v1.00.06

  • Found and fixed a major bug in the init file load code that prevented button labels above button 16 from being loaded from the init file. If you changed any of these labels they would revert back to their default values after a power cycle. It is recommended that all users update their firmware to this version.
  • Added swipe left or right to the Buttons menu to change the menu page

Latest Firmware

Click the link below to download the CTR2-Dial_v1xxxx.zip file. Unzip the .BIN files into a separate folder on your computer then follow the directions in the Operation Manual (also included in the .zip file) to flash the CTR2-Dial firmware into your M5Dial.


EspressIF Flash Download Tool

You’ll need to run the EspressIF Flash Download tool to flash this firmware to your CTR2-Dial. This is a Window app. Mac or Linux users will need to run the script file included in the firmware zip file to flash their units.

NOTE: You’ll need to force the M5Dial into programming mode in order to flash the firmware. To do this, press and hold the Program button on the back of the M5Dial then press the Reset button.

VIRUS DETECTED ISSUE WITH ESPRESSIF FLASH DOWNLOAD TOOL v3.9.8

It’s been reported that Windows detects a Trojan virus in the latest download tool (v3.9.8). When this has happened previously it was due to the tool using some Python libraries. The discussion from last year can be found here: https://github.com/espressif/esptool/issues/944.

For now, please use the 3.9.7 version from this site: Flash Downloader v3.9.7


Revision History

January 28, 2025 – v1.00.05

  • Added select/execute operation to the top and bottom buttons to prevent inadvertent menu changes when randomly touching the screen
  • Added dual-function buttons to the top and bottom buttons. These allow you to navigate the menus and controls without returning to the Home page
  • Increased granularity of Knob slider controls (was 2 counts per encoder tick, now 1 count) and increase counts per tick when turning knob fast so it doesn’t take 5 turns to go from low to high.
  • Fixed several minor display bugs that were displaying incorrect control information

January 24, 2025 – v1.00.04

  • Fixed a bug that was displaying the wrong control # on Map 2 Knob page 2
  • Fixed several small bugs in the Speed Tuning routine

January 23, 2025 – v1.00.03

  • Fixed a bug that was causing a single reverse pulse to be sent when crossing over 0 degree mark on the Dial

January 22, 2025 – v1.00.02

  • v1.00.02: Fixed a bug that kept the PTT page from returning to the Home page when touching the PTT caption.

January 22, 2025 – v1.00.01

  • Added WheelB-r MIDI control to reverse direction of WheelB when using CTR2-Dial with the PI HPSDR control program
  • Touching the CTR2-Dial caption on the Home page returns you to the previous menu or control
  • Fixed bugs in the Knob B parameter editing code
  • Added a new Power Requirements section to the manual

January 20, 2025 – v1.00.00 – Initial Release

  • This version had bugs in the Knob B parameter editing