zgemma star h2 blocked

Good evening everyone, following a bootloader update gone wrong I find the decoder with a solid red LED no ignition and no access to the menu, I would need, if possible, the bootloader for the zgemma star h2 and if someone could guide me in the flash I have little competence and difficulty in proceeding. Snowing on the net I saw that the procedure is a bit complex, someone recommends the USB TTL adapter others the Cypress. could you help me understand, thanks

I tried to use the Cypress with Broadband3 installation but when I connect the decoder to the Cypress and everything to the Broadband3 PC it gives me disconnected status, are there any solutions?