Unable to upload sketch via stm32duino bootloader method

[razvitm]

Board is generic from vcc-gnd.taobao.com.
MCU is STM32F103RCT6
Flashed bootloader on MCU using ST flash loader demonstrator and usb-serial converter with CH340G, used Global Erase option.
Used bootloader generic_boot20_pc13.bin
Installed the drivers by running the install_drivers.bat
Now when I plug the USB cable into the board, I see in Device Manager under Ports a so called "Maple Serial (Com5)".
When I go in Arduino and select Port: Com5 Maple Mini, and then click on Get board info, I get:
"BN: Maple Mini
VID: 0x1EAF
PID: 0x0004
SN: Upload any sketch to obtain it"
If I open Arduino Serial Monitor with 9600 Baud, I get:
"Congratulations, you have installed the STM32duino bootloader
See https://github.com/rogerclarkmelbourne/ ... bootloader


For more information about Arduino on STM32
See https://www.stm32duino.com"

When I try to upload a basic sketch via the stm32duino bootloader I get:
"maple_loader v0.1
Resetting to bootloader via DTR pulse
Searching for DFU device [1EAF:0003]...
dfu-util - (C) 2007-2008 by OpenMoko Inc.
This program is Free Software and has ABSOLUTELY NO WARRANTY


Couldn't find the DFU device: [1EAF:0003]"

At this point, the LED flashes, and in Device Manager, STM Serial(COM 4) appears with an exclamation mark.
"This device cannot start. (Code 10)

A device which does not exist was specified."

Also the port is no longer available for Serial Monitor.

What am I doing wrong?

P.S. I checked and the board has a 1.5kohm pull-up on A12.
P.S. The board has a solder jumper for pulling boot1 up.
Soldered the jumper and connected the board to the PC.
Now all I get in device manager is the STM Serial (Com4) with the exclamation mark and the The device cannot start error, and the board's LED flashing.

[stevestrong]

When you see in the Arduino message window

Code: Select all

Searching for DFU device [1EAF:0003]...

then press the reset buton.