Meanwhile, there are many variants of this Mini DSO with different hardware. My model (newer HW, recognizable eg to the white keys), the HW version 1.7, DFU (Device Firmware Updater) 3:29, and the oscilloscope firmware V4.28. This firmware version 4.28 is available on the website of "Minidso" (Chinese / English, updates indicated in the English / Chinese instructions of my device as an address for FW) can not be found, but many previous versions to v4.24. The hardware incl. Probe with mini-BNC is very good for the price, but there are 2 star deduction from me for the original installed FW 4.28 and a star turn to for relatively easy Updatebarkeit, if one takes the trouble, a to seek few hours on the internet and find the correct patch for its specific DSO 201 model. In my model, I have been playing without difficulty finally the latest version of BENF FW (search for "BenF_3.64APP_3.53LIB_patched_v2.zip". The zip file contains the FW file BENF_P2.hex). The BENF FW is really great and comfortable, so I now have a good useful device for AF measurements to about 100kHz. Even the micro SD Access works with the BENF FW, but only after I had this (2GB Transcend) with the free "SD Formatter" of the SD Association (search the Internet) on the PC formatted. The map of the DSO was with Win7 formatted as FAT not recognized. I can put anyone to his heart, in front of a FW update received detailed information on the web, what FW version and related installation method that is right for each selling model version of the DSO 201. A good resource is the Seeedstudio forum where you can read about many successful and unsuccessful updates. At worst, you end up with an unusable device. If you are unsure and afraid of this risk, better leave it alone. For me the above BENF version worked.