DATE: 2025/07/21
PHENOMENON: When powered on, the ESSENTIAL L1 shows "TEST MODE" on its display.
REASON: Your ESSENTIAL L1 is now running in factory test mode, a program we designed to help us calibrate and test the unit more efficiently.
This article will help you recover your ESSENTIAL L1 to user mode. However, before that, let me express my sincere apology for your not-so-great experience.
As an analog synthesizer, factory calibration and test processes are crucial. We carefully calibrate and test every ESSENTIAL L1 before shipping them to our customers. This process involves a lengthy list of tasks, which would take too much time to manufacture one unit without dedicated factory firmware. Thus, during the calibration and testing processes, we load the factory firmware to the ESSENTIAL L1.
After the process, we should load the official firmware before proceeding with the next step. However, a problem occurred as our QC department double-checked some of the units within a batch. They forgot to recover the initial firmware after testing the unit in test mode.
I hope that all the above has provided you with a clear view of this problem. The unit you get is carefully calibrated and thoroughly tested. All you need to do is load the user firmware according to the instructions below.
HOW TO UPDATE THE FIRMWARE MANUALLY?
1. Install the Donner Control software on your computer. You can download the latest software on our DOWNLOADS page (https://www.donnermusic.com/en-US/support/downloads/detail?first=SYNTHESIZERS&second=SYNTHESIZERS).
2. Download the initial user firmware of the ESSENTIAL L1 on your computer, using the following link (https://storage.donnermusic.com/official-user/202507/L1_0.9.0.syx.zip).
3. Connect the ESSENTIAL L1 to your computer using the USB cable in the package. Turn on the ESSENTIAL L1. Run the Donner Control software and wait for communication to be established. 
4. Enter the ESSENTIAL L1 Control Panel, and switch to the "Upgrade" tab.
Click "Rantion" 10 times to trigger an "Upgrade" button. 
5. Click the "Upgrade" button and choose the initial firmware file downloaded above. Then, wait for the firmware upgrade process to complete. 
6. After the upgrade, your ESSENTIAL L1 should reboot itself and run under the initial firmware. Now you can play with it, enjoy its excellent sound, and have a great time ;)
If you encounter issues while following the instructions above, don't worry; you can always repeat the process from STEP 3. Or contact our customer services for help.