switch (fw_run_transaction(card, TCODE_LOCK_COMPARE_SWAP,
                                irm_id, generation, SCODE_100,
                                CSR_REGISTER_BASE + CSR_BANDWIDTH_AVAILABLE,
-                               data, sizeof(data))) {
+                               data, 8)) {
                case RCODE_GENERATION:
                        /* A generation change frees all bandwidth. */
                        return allocate ? -EAGAIN : bandwidth;
                data[1] = old ^ c;
                switch (fw_run_transaction(card, TCODE_LOCK_COMPARE_SWAP,
                                           irm_id, generation, SCODE_100,
-                                          offset, data, sizeof(data))) {
+                                          offset, data, 8)) {
                case RCODE_GENERATION:
                        /* A generation change frees all channels. */
                        return allocate ? -EAGAIN : i;