Can the BT830 use HCI over H4?

Yes, but you need to send the following over BCSP # PSKEY_HOST_INTERFACE UART link running H4 psset 0x01f9 0x0003 psset 0x01C0 0x08a8 sleep 300 H4 will then become active after a soft reset. Note that this configuration data will be lost after a power cycle. This means these configuration commands need to be sent over BCSP each time the module powers up.