开云体育

After reading the option "01", seems that you dfu file should be written into target option "00" (internal flash 64 sectors).

A 2nd point: NanoVNA v0.8.4.6 Xtail 25997748.dfu is 82 Ko but the uploaded file from my NanoVNA is 129 Ko , is this ok ?

Rudi

Then you upload file from NanoVNA programm read all flash 128kB and save to file
Then formware created, not used space not stored to file. 82kB correct file size

Yes it Ok

Select target id
00 Internal Flash 64 sectors or

And press Upload