A network comprising a first base station, BS, and a second BS, comprising: at least one storage device; and at least one processing circuit, coupled to the at least one storage device, wherein the at least one storage device stores, and the at least one processing circuit is configured to execute, instructions of: the first BS connecting to a communication device via a first cell of the first BS with a signaling radio bearer, SRB; the second BS as a secondary node, SN, connecting to the communication device via a second cell while the first BS as a master node, MN, connecting to the communication device; the MN transmitting a SN Modification Request message to the SN to add or modify a configuration of the SN for the communication device in dual connectivity, DC; the SN transmitting a SN Modification Request Acknowledge message to the MN in response to the SN Modification Request message, wherein the SN Modification Request Acknowledge message comprises a new or modified configuration and a random access, RA, channel, RACH, configuration, and the RACH configuration configures at least one RACH resource and an association configuration associating the at least one RACH resource to a synchronization signal block, SSB, or a channel state information reference signal, CSI-RS, transmitted on the second cell; the MN transmitting a radio resource control, RRC, message comprising the new or modified configuration and the first RACH configuration on the SRB via the first cell to the communication device; the MN receiving a RRC response message responding to the RRC message from the communication device on the SRB on the first cell or a third cell of the MN; the SN receiving a RA preamble transmitted by the communication device on the second cell according to the at least one RACH resource; the SN transmitting a RA response, RAR, to the communication device on the second cell in response to the RA preamble; and the SN communicating with the communication device according to the new or modified configuration. at least one storage device; and at least one processing circuit, coupled to the at least one storage device, wherein the at least one storage device stores, and the at least one processing circuit is configured to execute, instructions of: the first BS connecting to a communication device via a first cell of the first BS with a signaling radio bearer, SRB; the second BS as a secondary node, SN, connecting to the communication device via a second cell while the first BS as a master node, MN, connecting to the communication device; the MN transmitting a SN Modification Request message to the SN to add or modify a configuration of the SN for the communication device in dual connectivity, DC; the SN transmitting a SN Modification Request Acknowledge message to the MN in response to the SN Modification Request message, wherein the SN Modification Request Acknowledge message comprises a new or modified configuration and a random access, RA, channel, RACH, configuration, and the RACH configuration configures at least one RACH resource and an association configuration associating the at least one RACH resource to a synchronization signal block, SSB, or a channel state information reference signal, CSI-RS, transmitted on the second cell; the MN transmitting a radio resource control, RRC, message comprising the new or modified configuration and the first RACH configuration on the SRB via the first cell to the communication device; the MN receiving a RRC response message responding to the RRC message from the communication device on the SRB on the first cell or a third cell of the MN; the SN receiving a RA preamble transmitted by the communication device on the second cell according to the at least one RACH resource; the SN transmitting a RA response, RAR, to the communication device on the second cell in response to the RA preamble; and the SN communicating with the communication device according to the new or modified configuration. the first BS connecting to a communication device via a first cell of the first BS with a signaling radio bearer, SRB; the second BS as a secondary node, SN, connecting to the communication device via a second cell while the first BS as a master node, MN, connecting to the communication device; the MN transmitting a SN Modification Request message to the SN to add or modify a configuration of the SN for the communication device in dual connectivity, DC; the SN transmitting a SN Modification Request Acknowledge message to the MN in response to the SN Modification Request message, wherein the SN Modification Request Acknowledge message comprises a new or modified configuration and a random access, RA, channel, RACH, configuration, and the RACH configuration configures at least one RACH resource and an association configuration associating the at least one RACH resource to a synchronization signal block, SSB, or a channel state information reference signal, CSI-RS, transmitted on the second cell; the MN transmitting a radio resource control, RRC, message comprising the new or modified configuration and the first RACH configuration on the SRB via the first cell to the communication device; the MN receiving a RRC response message responding to the RRC message from the communication device on the SRB on the first cell or a third cell of the MN; the SN receiving a RA preamble transmitted by the communication device on the second cell according to the at least one RACH resource; the SN transmitting a RA response, RAR, to the communication device on the second cell in response to the RA preamble; and the SN communicating with the communication device according to the new or modified configuration.