Eddystone-UID is a component of the Eddystone parameter for BLE beacons. It contains 36 hexadecimal digits composed of 20 hexadecimal digits Namespace ID, 12 hexadecimal digits Instance ID and 4 hexadecimal digits RFU, split into 3 groups, separated by hyphens.
Each of the 3 groups must contain the following number of characters per section:
First section: 20
Second section: 12
Third section: 4
Characters should be number from 0 to 9, and letters from A to F. A group can be made entirely of just number or letters or combination of both.
Please remember feasycom made beacon’s UID Namespace+Instance ,which marked in red as below image .Must be uniqueness.The Namespace+Instance all the 32 figure you can see it as a overall.If this 32 figure has already been set by other beacons or other customers ,then you are not able to configure.That is why when you already set okay the UID,but when you enter Beacon Tools you can not find this UID from the ‘’UNREGISTERED’’ or’’Registered’’ list .So pls do remember the UID’s Namespace and Instance is uniqueness.