Just in case someone in the future bumps into this thread, the Rigol USA website now has the 3.06 firmware and readme
https://www.rigolna.com/firmware/Here's what the readme says for the last 3 releases. Interestingly the readme file inside the ZIP archive is timestamped June 2020, even if the GEL file is from January 2019
[Supported Model] All the MSO/DS2000A Series Digital Oscilloscopes
[Latest Revision Date] 2019/01/29
[Updated Contents]
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v00.03.06.00.00 2019/01/29
- Fixed the bug of wave displaying after AUTO
[History]
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v00.03.05.04.00 2018/04/02
- Inproved the wave updating
v00.03.05.03.03 2017/06/26
- Add new models of DS2102E and DS2202E
- Fixed the error of some Traditional Chinese menu
- Fixed the bug of EDU version
- Fixed the bug of wave stop updating
v00.03.05.00.01 2016/07/20
- Modified the naming rule for saving screen snap
- Fixed the bug of the wave stop updating
- Fixed the bug of Math expression