Zero 3W: no boot, no eMMC upload

Hello, I cannot load any of the two Armbian OS images (24.8 xfce, 25.2 minimum) into Radxa Zero 3W using RkDevelopTool and rk356x_spl_loader_ddr1056_v1.12.109_no_check_todly.bin bootloader.
The whole process runs until “Start to download C:\Users\Public\Downloads\radxa\images\Armbian_24.8.1_Radxa-zero3_bookworm_vendor_6.1.75_xfce_desktop.img” (or another image, included the bullseye Debian recommended by Radxa) and after some timeout it ends with “Download image failed”.
In the meantime I successfully loaded bullseye into another Radxa Zero 3W, but it needed 20+ attempts. The underlying operating system is Win 10 Pro 22H2.
Before my attempt to upload OS into eMMC neither of the two boards booted, they just blinked with the green LED and nothing happened, no output to HDMI display at all.

Hi Jindrich

Is it possible to boot from SD card properly?

You can try this version of RKDevTool:
https://dl.radxa.com/tools/windows/RKDevTool_Release_v2.86.zip

Note that you need to extract the image file to .img format when burning with RKDevTool.