Well, I made a mistake and flashed the wrong firmware.
Slaesh stick CC2652R which uses koenkks firmware CC2652 RB
However, I flashed it with LAUNCHXL-CC26X2R1 firmware found here: (https://github.com/dzungpv/Z-Stack-firmware/commit/3b9b5c02fcd55c98aacbc48bc9d78a39e94e885d)
And now I can’t get into bootloader (don’t know if it erased it).
Maybe the GPIO pins for accessing bootloader was changed in this firmware.
And I saw some other place that original bootloader is shorting GPIO13 with GND.
But on Slaesh stick, GPIO13 doesnt seem to be available.
Do anyone know how to flash the stick if the bootloader is not accesible?
Yes, I am stupid…