Unlock the band support on X55, X60, X65 equipped Xperia 1 series devices
This guide will unlock all bands and all combos that are supported by the modem hardware for all networks on the Xperia 1 series equipped with 5G chipsets.
First, follow the diag guide here enabling diag and getting access to QPST.
Then, download this archive here here.
Then, drag and drop the files from the archive into the /policyman/ folder in QPST and overwrite the existing ones.
The changes take effect on a reboot and persist until you flash firmware or take an OTA.