Hi,
I just fixed a nasty bug in the ostc3 backend that was introduced with the BLE support (commit 0978f8c0fa70710bad3fb865ffe3a20961c408dc). Ironically everything works fine when using BLE, but not for bluetooth classic or its serial emulation.
Please upgrade asap, because this bug not only causes the download to fail, but it also appears to change random settings on the dive computer!
Jef