For technical guides or potential legacy firmware updates, radio enthusiast communities often host files: TC-780M Programming Software Download
If the software asks for a password to read the radio, it was likely set by a previous technician. You may need to perform a factory reset, which will wipe all current channel data. hyt tc780 programming software link download
HYT (now part of Hytera) has shifted support for legacy models like the TC780 to their legacy portal. For technical guides or potential legacy firmware updates,