A method performed by a radio terminal, the method comprising: receiving from a radio station a configuration indicating a maximum number of preamble transmissions of a 2-step Contention Based Random Access, CBRA; transmitting a first message of the 2-step CBRA to the radio station, the first message including a preamble and a Medium Access Control Protocol Data Unit, MAC PDU; attempting to receive a second message of the 2-step CBRA, the second message including at least: a Temporary Cell Radio Network Temporary Identifier, C-RNTI, and a Timing Advance Command; in a case where the second message is not successfully received, restarting the 2-step CBRA; in a case where the second message is successfully received and the second message does not indicate a fallback to a 4-step CBRA, continuing the 2-step CBRA; in a case where the second message is successfully received and the second message indicates the fallback to the 4-step CBRA, falling back to the 4-step CBRA; wherein the second message indicating the fallback to the 4-step CBRA includes a MAC subheader, wherein the MAC subheader includes a Random Access Preamble Identifier, RAPID, field, and wherein the second message indicating the fallback to the 4-step CBRA includes an uplink grant indicating uplink resources to be used for transmission of a third message of the 4-step CBRA, transmitting the third message of the 4-step CBRA in accordance with the uplink grant after receiving the second message indicating the fallback to the 4-step CBRA; receiving a fourth message of the 4-step CBRA after transmitting the third message of the 4-step CBRA, wherein the method further comprises: falling back to the 4-step CBRA after a number of preamble transmissions of the 2-step CBRA reaches the maximum number of preamble transmissions of the 2-step CBRA; and continuing or restarting a counter for counting the number of preamble transmissions in a case of falling back to the 4-step CBRA. receiving from a radio station a configuration indicating a maximum number of preamble transmissions of a 2-step Contention Based Random Access, CBRA; transmitting a first message of the 2-step CBRA to the radio station, the first message including a preamble and a Medium Access Control Protocol Data Unit, MAC PDU; attempting to receive a second message of the 2-step CBRA, the second message including at least: a Temporary Cell Radio Network Temporary Identifier, C-RNTI, and a Timing Advance Command; a Temporary Cell Radio Network Temporary Identifier, C-RNTI, and a Timing Advance Command; in a case where the second message is not successfully received, restarting the 2-step CBRA; in a case where the second message is successfully received and the second message does not indicate a fallback to a 4-step CBRA, continuing the 2-step CBRA; in a case where the second message is successfully received and the second message indicates the fallback to the 4-step CBRA, falling back to the 4-step CBRA; wherein the second message indicating the fallback to the 4-step CBRA includes a MAC subheader, wherein the MAC subheader includes a Random Access Preamble Identifier, RAPID, field, and wherein the second message indicating the fallback to the 4-step CBRA includes an uplink grant indicating uplink resources to be used for transmission of a third message of the 4-step CBRA, transmitting the third message of the 4-step CBRA in accordance with the uplink grant after receiving the second message indicating the fallback to the 4-step CBRA; receiving a fourth message of the 4-step CBRA after transmitting the third message of the 4-step CBRA, wherein the method further comprises: falling back to the 4-step CBRA after a number of preamble transmissions of the 2-step CBRA reaches the maximum number of preamble transmissions of the 2-step CBRA; and continuing or restarting a counter for counting the number of preamble transmissions in a case of falling back to the 4-step CBRA. falling back to the 4-step CBRA after a number of preamble transmissions of the 2-step CBRA reaches the maximum number of preamble transmissions of the 2-step CBRA; and continuing or restarting a counter for counting the number of preamble transmissions in a case of falling back to the 4-step CBRA.