I found the info, that I have to put PA11 to Gnd to bring the G400D in loader mode. I also found, that the G400HDR has three buttons. But there is no connection between a button and PA11 (which would be really helpful).
Now my question, is there any error in the documentation (https://www.ghielectronics.com/docs/236/loader-tinybooter-update-g400) or is there a mistake on the g400HDR board and now we have to use some workaround to force loader mode?
Two of the buttons on G400HDR were named LDR0 and LDR1, guess, thars ‘LDR’ means ‘Loader’, so I dont understand that system, sorry.
With best regards