A firmware update was recently released for the NVR6XX-4KS2 series devices.
Information, instructions, and download links can be found Here
From Dahua Wiki
How to Use NVR Selector
The NVR Selector is a windows program that assists in selecting the best NVR for your needs. Please follow the instructions below to start using the NVR Selector.
- NVR Selector
Step by Step Instructions
1. On the NVR Selector, check mark the HDD Bays and Input Channel.
2. Input the number of HDD Bays, input channel, frame rate, decoding channel and resolution you want and click search.
3. You can see the models that match the description now with the basic spec at the bottom, you can also scroll through multiple NVR that match the description.