diff --git a/c/src/v4/acquisition.c b/c/src/v4/acquisition.c
index 25a486d22e..f55d72ff94 100644
--- a/c/src/v4/acquisition.c
+++ b/c/src/v4/acquisition.c
@@ -822,6 +822,9 @@ s8 sbp_msg_acq_sv_profile_encode(uint8_t *buf, uint8_t len, uint8_t *n_written,
 
 bool sbp_msg_acq_sv_profile_decode_internal(sbp_decode_ctx_t *ctx,
                                             sbp_msg_acq_sv_profile_t *msg) {
+  if (((ctx->buf_len - ctx->offset) % SBP_ACQ_SV_PROFILE_ENCODED_LEN) != 0) {
+    return false;
+  }
   msg->n_acq_sv_profile =
       (uint8_t)((ctx->buf_len - ctx->offset) / SBP_ACQ_SV_PROFILE_ENCODED_LEN);
   for (uint8_t i = 0; i < msg->n_acq_sv_profile; i++) {
@@ -904,6 +907,10 @@ s8 sbp_msg_acq_sv_profile_dep_encode(uint8_t *buf, uint8_t len,
 
 bool sbp_msg_acq_sv_profile_dep_decode_internal(
     sbp_decode_ctx_t *ctx, sbp_msg_acq_sv_profile_dep_t *msg) {
+  if (((ctx->buf_len - ctx->offset) % SBP_ACQ_SV_PROFILE_DEP_ENCODED_LEN) !=
+      0) {
+    return false;
+  }
   msg->n_acq_sv_profile = (uint8_t)((ctx->buf_len - ctx->offset) /
                                     SBP_ACQ_SV_PROFILE_DEP_ENCODED_LEN);
   for (uint8_t i = 0; i < msg->n_acq_sv_profile; i++) {
diff --git a/c/src/v4/file_io.c b/c/src/v4/file_io.c
index 659a2d3577..c88e9b775b 100644
--- a/c/src/v4/file_io.c
+++ b/c/src/v4/file_io.c
@@ -257,6 +257,9 @@ bool sbp_msg_fileio_read_resp_decode_internal(sbp_decode_ctx_t *ctx,
   if (!sbp_u32_decode(ctx, &msg->sequence)) {
     return false;
   }
+  if (((ctx->buf_len - ctx->offset) % SBP_ENCODED_LEN_U8) != 0) {
+    return false;
+  }
   msg->n_contents =
       (uint8_t)((ctx->buf_len - ctx->offset) / SBP_ENCODED_LEN_U8);
   for (uint8_t i = 0; i < msg->n_contents; i++) {
@@ -1009,6 +1012,9 @@ bool sbp_msg_fileio_write_req_decode_internal(sbp_decode_ctx_t *ctx,
           &msg->filename, SBP_MSG_FILEIO_WRITE_REQ_FILENAME_MAX, ctx)) {
     return false;
   }
+  if (((ctx->buf_len - ctx->offset) % SBP_ENCODED_LEN_U8) != 0) {
+    return false;
+  }
   msg->n_data = (uint8_t)((ctx->buf_len - ctx->offset) / SBP_ENCODED_LEN_U8);
   for (uint8_t i = 0; i < msg->n_data; i++) {
     if (!sbp_u8_decode(ctx, &msg->data[i])) {
diff --git a/c/src/v4/flash.c b/c/src/v4/flash.c
index 6ba7deb9e8..0750a8945d 100644
--- a/c/src/v4/flash.c
+++ b/c/src/v4/flash.c
@@ -65,6 +65,9 @@ bool sbp_msg_flash_program_decode_internal(sbp_decode_ctx_t *ctx,
   if (!sbp_u8_decode(ctx, &msg->addr_len)) {
     return false;
   }
+  if (((ctx->buf_len - ctx->offset) % SBP_ENCODED_LEN_U8) != 0) {
+    return false;
+  }
   msg->addr_len = (uint8_t)((ctx->buf_len - ctx->offset) / SBP_ENCODED_LEN_U8);
   for (uint8_t i = 0; i < msg->addr_len; i++) {
     if (!sbp_u8_decode(ctx, &msg->data[i])) {
diff --git a/c/src/v4/integrity.c b/c/src/v4/integrity.c
index 41a45a5149..c5435157ee 100644
--- a/c/src/v4/integrity.c
+++ b/c/src/v4/integrity.c
@@ -435,6 +435,9 @@ bool sbp_msg_ssr_flag_satellites_decode_internal(
   if (!sbp_u8_decode(ctx, &msg->n_faulty_sats)) {
     return false;
   }
+  if (((ctx->buf_len - ctx->offset) % SBP_ENCODED_LEN_U8) != 0) {
+    return false;
+  }
   msg->n_faulty_sats =
       (uint8_t)((ctx->buf_len - ctx->offset) / SBP_ENCODED_LEN_U8);
   for (uint8_t i = 0; i < msg->n_faulty_sats; i++) {
@@ -564,6 +567,9 @@ bool sbp_msg_ssr_flag_tropo_grid_points_decode_internal(
   if (!sbp_u8_decode(ctx, &msg->n_faulty_points)) {
     return false;
   }
+  if (((ctx->buf_len - ctx->offset) % SBP_ENCODED_LEN_U16) != 0) {
+    return false;
+  }
   msg->n_faulty_points =
       (uint8_t)((ctx->buf_len - ctx->offset) / SBP_ENCODED_LEN_U16);
   for (uint8_t i = 0; i < msg->n_faulty_points; i++) {
@@ -669,6 +675,9 @@ bool sbp_msg_ssr_flag_iono_grid_points_decode_internal(
   if (!sbp_u8_decode(ctx, &msg->n_faulty_points)) {
     return false;
   }
+  if (((ctx->buf_len - ctx->offset) % SBP_ENCODED_LEN_U16) != 0) {
+    return false;
+  }
   msg->n_faulty_points =
       (uint8_t)((ctx->buf_len - ctx->offset) / SBP_ENCODED_LEN_U16);
   for (uint8_t i = 0; i < msg->n_faulty_points; i++) {
@@ -774,6 +783,9 @@ bool sbp_msg_ssr_flag_iono_tile_sat_los_decode_internal(
   if (!sbp_u8_decode(ctx, &msg->n_faulty_los)) {
     return false;
   }
+  if (((ctx->buf_len - ctx->offset) % SBP_SV_ID_ENCODED_LEN) != 0) {
+    return false;
+  }
   msg->n_faulty_los =
       (uint8_t)((ctx->buf_len - ctx->offset) / SBP_SV_ID_ENCODED_LEN);
   for (uint8_t i = 0; i < msg->n_faulty_los; i++) {
@@ -886,6 +898,9 @@ bool sbp_msg_ssr_flag_iono_grid_point_sat_los_decode_internal(
   if (!sbp_u8_decode(ctx, &msg->n_faulty_los)) {
     return false;
   }
+  if (((ctx->buf_len - ctx->offset) % SBP_SV_ID_ENCODED_LEN) != 0) {
+    return false;
+  }
   msg->n_faulty_los =
       (uint8_t)((ctx->buf_len - ctx->offset) / SBP_SV_ID_ENCODED_LEN);
   for (uint8_t i = 0; i < msg->n_faulty_los; i++) {
diff --git a/c/src/v4/logging.c b/c/src/v4/logging.c
index 72113d780e..3c18cce602 100644
--- a/c/src/v4/logging.c
+++ b/c/src/v4/logging.c
@@ -208,6 +208,9 @@ bool sbp_msg_fwd_decode_internal(sbp_decode_ctx_t *ctx, sbp_msg_fwd_t *msg) {
   if (!sbp_u8_decode(ctx, &msg->protocol)) {
     return false;
   }
+  if (((ctx->buf_len - ctx->offset) % SBP_ENCODED_LEN_U8) != 0) {
+    return false;
+  }
   msg->n_fwd_payload =
       (uint8_t)((ctx->buf_len - ctx->offset) / SBP_ENCODED_LEN_U8);
   for (uint8_t i = 0; i < msg->n_fwd_payload; i++) {
diff --git a/c/src/v4/observation.c b/c/src/v4/observation.c
index f7e3c30f5c..967b3eea5d 100644
--- a/c/src/v4/observation.c
+++ b/c/src/v4/observation.c
@@ -442,6 +442,10 @@ bool sbp_msg_obs_decode_internal(sbp_decode_ctx_t *ctx, sbp_msg_obs_t *msg) {
   if (!sbp_observation_header_decode_internal(ctx, &msg->header)) {
     return false;
   }
+  if (((ctx->buf_len - ctx->offset) % SBP_PACKED_OBS_CONTENT_ENCODED_LEN) !=
+      0) {
+    return false;
+  }
   msg->n_obs = (uint8_t)((ctx->buf_len - ctx->offset) /
                          SBP_PACKED_OBS_CONTENT_ENCODED_LEN);
   for (uint8_t i = 0; i < msg->n_obs; i++) {
@@ -6486,6 +6490,10 @@ bool sbp_msg_obs_dep_a_decode_internal(sbp_decode_ctx_t *ctx,
   if (!sbp_observation_header_dep_decode_internal(ctx, &msg->header)) {
     return false;
   }
+  if (((ctx->buf_len - ctx->offset) %
+       SBP_PACKED_OBS_CONTENT_DEP_A_ENCODED_LEN) != 0) {
+    return false;
+  }
   msg->n_obs = (uint8_t)((ctx->buf_len - ctx->offset) /
                          SBP_PACKED_OBS_CONTENT_DEP_A_ENCODED_LEN);
   for (uint8_t i = 0; i < msg->n_obs; i++) {
@@ -6577,6 +6585,10 @@ bool sbp_msg_obs_dep_b_decode_internal(sbp_decode_ctx_t *ctx,
   if (!sbp_observation_header_dep_decode_internal(ctx, &msg->header)) {
     return false;
   }
+  if (((ctx->buf_len - ctx->offset) %
+       SBP_PACKED_OBS_CONTENT_DEP_B_ENCODED_LEN) != 0) {
+    return false;
+  }
   msg->n_obs = (uint8_t)((ctx->buf_len - ctx->offset) /
                          SBP_PACKED_OBS_CONTENT_DEP_B_ENCODED_LEN);
   for (uint8_t i = 0; i < msg->n_obs; i++) {
@@ -6668,6 +6680,10 @@ bool sbp_msg_obs_dep_c_decode_internal(sbp_decode_ctx_t *ctx,
   if (!sbp_observation_header_dep_decode_internal(ctx, &msg->header)) {
     return false;
   }
+  if (((ctx->buf_len - ctx->offset) %
+       SBP_PACKED_OBS_CONTENT_DEP_C_ENCODED_LEN) != 0) {
+    return false;
+  }
   msg->n_obs = (uint8_t)((ctx->buf_len - ctx->offset) /
                          SBP_PACKED_OBS_CONTENT_DEP_C_ENCODED_LEN);
   for (uint8_t i = 0; i < msg->n_obs; i++) {
@@ -8726,6 +8742,9 @@ s8 sbp_msg_sv_az_el_encode(uint8_t *buf, uint8_t len, uint8_t *n_written,
 
 bool sbp_msg_sv_az_el_decode_internal(sbp_decode_ctx_t *ctx,
                                       sbp_msg_sv_az_el_t *msg) {
+  if (((ctx->buf_len - ctx->offset) % SBP_SV_AZ_EL_ENCODED_LEN) != 0) {
+    return false;
+  }
   msg->n_azel =
       (uint8_t)((ctx->buf_len - ctx->offset) / SBP_SV_AZ_EL_ENCODED_LEN);
   for (uint8_t i = 0; i < msg->n_azel; i++) {
@@ -8809,6 +8828,10 @@ bool sbp_msg_osr_decode_internal(sbp_decode_ctx_t *ctx, sbp_msg_osr_t *msg) {
   if (!sbp_observation_header_decode_internal(ctx, &msg->header)) {
     return false;
   }
+  if (((ctx->buf_len - ctx->offset) % SBP_PACKED_OSR_CONTENT_ENCODED_LEN) !=
+      0) {
+    return false;
+  }
   msg->n_obs = (uint8_t)((ctx->buf_len - ctx->offset) /
                          SBP_PACKED_OSR_CONTENT_ENCODED_LEN);
   for (uint8_t i = 0; i < msg->n_obs; i++) {
diff --git a/c/src/v4/piksi.c b/c/src/v4/piksi.c
index dd83a64ab9..87160dccdb 100644
--- a/c/src/v4/piksi.c
+++ b/c/src/v4/piksi.c
@@ -2323,6 +2323,9 @@ s8 sbp_msg_network_bandwidth_usage_encode(
 
 bool sbp_msg_network_bandwidth_usage_decode_internal(
     sbp_decode_ctx_t *ctx, sbp_msg_network_bandwidth_usage_t *msg) {
+  if (((ctx->buf_len - ctx->offset) % SBP_NETWORK_USAGE_ENCODED_LEN) != 0) {
+    return false;
+  }
   msg->n_interfaces =
       (uint8_t)((ctx->buf_len - ctx->offset) / SBP_NETWORK_USAGE_ENCODED_LEN);
   for (uint8_t i = 0; i < msg->n_interfaces; i++) {
@@ -2418,6 +2421,9 @@ bool sbp_msg_cell_modem_status_decode_internal(
   if (!sbp_float_decode(ctx, &msg->signal_error_rate)) {
     return false;
   }
+  if (((ctx->buf_len - ctx->offset) % SBP_ENCODED_LEN_U8) != 0) {
+    return false;
+  }
   msg->n_reserved =
       (uint8_t)((ctx->buf_len - ctx->offset) / SBP_ENCODED_LEN_U8);
   for (uint8_t i = 0; i < msg->n_reserved; i++) {
@@ -2545,6 +2551,9 @@ bool sbp_msg_specan_dep_decode_internal(sbp_decode_ctx_t *ctx,
   if (!sbp_float_decode(ctx, &msg->amplitude_unit)) {
     return false;
   }
+  if (((ctx->buf_len - ctx->offset) % SBP_ENCODED_LEN_U8) != 0) {
+    return false;
+  }
   msg->n_amplitude_value =
       (uint8_t)((ctx->buf_len - ctx->offset) / SBP_ENCODED_LEN_U8);
   for (uint8_t i = 0; i < msg->n_amplitude_value; i++) {
@@ -2691,6 +2700,9 @@ bool sbp_msg_specan_decode_internal(sbp_decode_ctx_t *ctx,
   if (!sbp_float_decode(ctx, &msg->amplitude_unit)) {
     return false;
   }
+  if (((ctx->buf_len - ctx->offset) % SBP_ENCODED_LEN_U8) != 0) {
+    return false;
+  }
   msg->n_amplitude_value =
       (uint8_t)((ctx->buf_len - ctx->offset) / SBP_ENCODED_LEN_U8);
   for (uint8_t i = 0; i < msg->n_amplitude_value; i++) {
diff --git a/c/src/v4/signing.c b/c/src/v4/signing.c
index d449e2c24b..27f5d2ffc2 100644
--- a/c/src/v4/signing.c
+++ b/c/src/v4/signing.c
@@ -261,6 +261,9 @@ bool sbp_msg_ecdsa_certificate_decode_internal(
   if (!sbp_u8_decode(ctx, &msg->flags)) {
     return false;
   }
+  if (((ctx->buf_len - ctx->offset) % SBP_ENCODED_LEN_U8) != 0) {
+    return false;
+  }
   msg->n_certificate_bytes =
       (uint8_t)((ctx->buf_len - ctx->offset) / SBP_ENCODED_LEN_U8);
   for (uint8_t i = 0; i < msg->n_certificate_bytes; i++) {
@@ -699,6 +702,9 @@ bool sbp_msg_ecdsa_signature_decode_internal(sbp_decode_ctx_t *ctx,
   if (!sbp_ecdsa_signature_decode_internal(ctx, &msg->signature)) {
     return false;
   }
+  if (((ctx->buf_len - ctx->offset) % SBP_ENCODED_LEN_U8) != 0) {
+    return false;
+  }
   msg->n_signed_messages =
       (uint8_t)((ctx->buf_len - ctx->offset) / SBP_ENCODED_LEN_U8);
   for (uint8_t i = 0; i < msg->n_signed_messages; i++) {
@@ -855,6 +861,9 @@ bool sbp_msg_ecdsa_signature_dep_b_decode_internal(
       return false;
     }
   }
+  if (((ctx->buf_len - ctx->offset) % SBP_ENCODED_LEN_U8) != 0) {
+    return false;
+  }
   msg->n_signed_messages =
       (uint8_t)((ctx->buf_len - ctx->offset) / SBP_ENCODED_LEN_U8);
   for (uint8_t i = 0; i < msg->n_signed_messages; i++) {
@@ -1014,6 +1023,9 @@ bool sbp_msg_ecdsa_signature_dep_a_decode_internal(
       return false;
     }
   }
+  if (((ctx->buf_len - ctx->offset) % SBP_ENCODED_LEN_U8) != 0) {
+    return false;
+  }
   msg->n_signed_messages =
       (uint8_t)((ctx->buf_len - ctx->offset) / SBP_ENCODED_LEN_U8);
   for (uint8_t i = 0; i < msg->n_signed_messages; i++) {
@@ -1145,6 +1157,9 @@ bool sbp_msg_ed25519_certificate_dep_decode_internal(
       return false;
     }
   }
+  if (((ctx->buf_len - ctx->offset) % SBP_ENCODED_LEN_U8) != 0) {
+    return false;
+  }
   msg->n_certificate_bytes =
       (uint8_t)((ctx->buf_len - ctx->offset) / SBP_ENCODED_LEN_U8);
   for (uint8_t i = 0; i < msg->n_certificate_bytes; i++) {
@@ -1262,6 +1277,9 @@ bool sbp_msg_ed25519_signature_dep_a_decode_internal(
       return false;
     }
   }
+  if (((ctx->buf_len - ctx->offset) % SBP_ENCODED_LEN_U32) != 0) {
+    return false;
+  }
   msg->n_signed_messages =
       (uint8_t)((ctx->buf_len - ctx->offset) / SBP_ENCODED_LEN_U32);
   for (uint8_t i = 0; i < msg->n_signed_messages; i++) {
@@ -1394,6 +1412,9 @@ bool sbp_msg_ed25519_signature_dep_b_decode_internal(
       return false;
     }
   }
+  if (((ctx->buf_len - ctx->offset) % SBP_ENCODED_LEN_U32) != 0) {
+    return false;
+  }
   msg->n_signed_messages =
       (uint8_t)((ctx->buf_len - ctx->offset) / SBP_ENCODED_LEN_U32);
   for (uint8_t i = 0; i < msg->n_signed_messages; i++) {
diff --git a/c/src/v4/solution_meta.c b/c/src/v4/solution_meta.c
index 7cacd3199a..5f4b8b9df1 100644
--- a/c/src/v4/solution_meta.c
+++ b/c/src/v4/solution_meta.c
@@ -160,6 +160,10 @@ bool sbp_msg_soln_meta_dep_a_decode_internal(sbp_decode_ctx_t *ctx,
   if (!sbp_u32_decode(ctx, &msg->last_used_gnss_vel_tow)) {
     return false;
   }
+  if (((ctx->buf_len - ctx->offset) % SBP_SOLUTION_INPUT_TYPE_ENCODED_LEN) !=
+      0) {
+    return false;
+  }
   msg->n_sol_in = (uint8_t)((ctx->buf_len - ctx->offset) /
                             SBP_SOLUTION_INPUT_TYPE_ENCODED_LEN);
   for (uint8_t i = 0; i < msg->n_sol_in; i++) {
@@ -317,6 +321,10 @@ bool sbp_msg_soln_meta_decode_internal(sbp_decode_ctx_t *ctx,
   if (!sbp_u32_decode(ctx, &msg->age_gnss)) {
     return false;
   }
+  if (((ctx->buf_len - ctx->offset) % SBP_SOLUTION_INPUT_TYPE_ENCODED_LEN) !=
+      0) {
+    return false;
+  }
   msg->n_sol_in = (uint8_t)((ctx->buf_len - ctx->offset) /
                             SBP_SOLUTION_INPUT_TYPE_ENCODED_LEN);
   for (uint8_t i = 0; i < msg->n_sol_in; i++) {
diff --git a/c/src/v4/ssr.c b/c/src/v4/ssr.c
index ef5981b878..0b34711bd6 100644
--- a/c/src/v4/ssr.c
+++ b/c/src/v4/ssr.c
@@ -1104,6 +1104,10 @@ bool sbp_msg_ssr_code_biases_decode_internal(sbp_decode_ctx_t *ctx,
   if (!sbp_u8_decode(ctx, &msg->iod_ssr)) {
     return false;
   }
+  if (((ctx->buf_len - ctx->offset) % SBP_CODE_BIASES_CONTENT_ENCODED_LEN) !=
+      0) {
+    return false;
+  }
   msg->n_biases = (uint8_t)((ctx->buf_len - ctx->offset) /
                             SBP_CODE_BIASES_CONTENT_ENCODED_LEN);
   for (uint8_t i = 0; i < msg->n_biases; i++) {
@@ -1254,6 +1258,10 @@ bool sbp_msg_ssr_phase_biases_decode_internal(sbp_decode_ctx_t *ctx,
   if (!sbp_s8_decode(ctx, &msg->yaw_rate)) {
     return false;
   }
+  if (((ctx->buf_len - ctx->offset) % SBP_PHASE_BIASES_CONTENT_ENCODED_LEN) !=
+      0) {
+    return false;
+  }
   msg->n_biases = (uint8_t)((ctx->buf_len - ctx->offset) /
                             SBP_PHASE_BIASES_CONTENT_ENCODED_LEN);
   for (uint8_t i = 0; i < msg->n_biases; i++) {
@@ -1382,6 +1390,9 @@ bool sbp_msg_ssr_stec_correction_dep_decode_internal(
   if (!sbp_stec_header_decode_internal(ctx, &msg->header)) {
     return false;
   }
+  if (((ctx->buf_len - ctx->offset) % SBP_STEC_SAT_ELEMENT_ENCODED_LEN) != 0) {
+    return false;
+  }
   msg->n_stec_sat_list = (uint8_t)((ctx->buf_len - ctx->offset) /
                                    SBP_STEC_SAT_ELEMENT_ENCODED_LEN);
   for (uint8_t i = 0; i < msg->n_stec_sat_list; i++) {
@@ -1601,6 +1612,9 @@ bool sbp_msg_ssr_stec_correction_decode_internal(
   if (!sbp_u8_decode(ctx, &msg->n_sats)) {
     return false;
   }
+  if (((ctx->buf_len - ctx->offset) % SBP_STEC_SAT_ELEMENT_ENCODED_LEN) != 0) {
+    return false;
+  }
   msg->n_sats = (uint8_t)((ctx->buf_len - ctx->offset) /
                           SBP_STEC_SAT_ELEMENT_ENCODED_LEN);
   for (uint8_t i = 0; i < msg->n_sats; i++) {
@@ -1728,6 +1742,9 @@ bool sbp_msg_ssr_gridded_correction_decode_internal(
           ctx, &msg->tropo_delay_correction)) {
     return false;
   }
+  if (((ctx->buf_len - ctx->offset) % SBP_STEC_RESIDUAL_ENCODED_LEN) != 0) {
+    return false;
+  }
   msg->n_stec_residuals =
       (uint8_t)((ctx->buf_len - ctx->offset) / SBP_STEC_RESIDUAL_ENCODED_LEN);
   for (uint8_t i = 0; i < msg->n_stec_residuals; i++) {
@@ -2006,6 +2023,10 @@ bool sbp_msg_ssr_gridded_correction_bounds_decode_internal(
   if (!sbp_u8_decode(ctx, &msg->n_sats)) {
     return false;
   }
+  if (((ctx->buf_len - ctx->offset) %
+       SBP_STEC_SAT_ELEMENT_INTEGRITY_ENCODED_LEN) != 0) {
+    return false;
+  }
   msg->n_sats = (uint8_t)((ctx->buf_len - ctx->offset) /
                           SBP_STEC_SAT_ELEMENT_INTEGRITY_ENCODED_LEN);
   for (uint8_t i = 0; i < msg->n_sats; i++) {
@@ -2805,6 +2826,9 @@ s8 sbp_msg_ssr_satellite_apc_dep_encode(
 
 bool sbp_msg_ssr_satellite_apc_dep_decode_internal(
     sbp_decode_ctx_t *ctx, sbp_msg_ssr_satellite_apc_dep_t *msg) {
+  if (((ctx->buf_len - ctx->offset) % SBP_SATELLITE_APC_ENCODED_LEN) != 0) {
+    return false;
+  }
   msg->n_apc =
       (uint8_t)((ctx->buf_len - ctx->offset) / SBP_SATELLITE_APC_ENCODED_LEN);
   for (uint8_t i = 0; i < msg->n_apc; i++) {
@@ -2912,6 +2936,9 @@ bool sbp_msg_ssr_satellite_apc_decode_internal(
   if (!sbp_u8_decode(ctx, &msg->iod_ssr)) {
     return false;
   }
+  if (((ctx->buf_len - ctx->offset) % SBP_SATELLITE_APC_ENCODED_LEN) != 0) {
+    return false;
+  }
   msg->n_apc =
       (uint8_t)((ctx->buf_len - ctx->offset) / SBP_SATELLITE_APC_ENCODED_LEN);
   for (uint8_t i = 0; i < msg->n_apc; i++) {
@@ -3568,6 +3595,9 @@ bool sbp_msg_ssr_stec_correction_dep_a_decode_internal(
   if (!sbp_stec_header_dep_a_decode_internal(ctx, &msg->header)) {
     return false;
   }
+  if (((ctx->buf_len - ctx->offset) % SBP_STEC_SAT_ELEMENT_ENCODED_LEN) != 0) {
+    return false;
+  }
   msg->n_stec_sat_list = (uint8_t)((ctx->buf_len - ctx->offset) /
                                    SBP_STEC_SAT_ELEMENT_ENCODED_LEN);
   for (uint8_t i = 0; i < msg->n_stec_sat_list; i++) {
@@ -3678,6 +3708,10 @@ bool sbp_msg_ssr_gridded_correction_no_std_dep_a_decode_internal(
           ctx, &msg->tropo_delay_correction)) {
     return false;
   }
+  if (((ctx->buf_len - ctx->offset) % SBP_STEC_RESIDUAL_NO_STD_ENCODED_LEN) !=
+      0) {
+    return false;
+  }
   msg->n_stec_residuals = (uint8_t)((ctx->buf_len - ctx->offset) /
                                     SBP_STEC_RESIDUAL_NO_STD_ENCODED_LEN);
   for (uint8_t i = 0; i < msg->n_stec_residuals; i++) {
@@ -3800,6 +3834,9 @@ bool sbp_msg_ssr_gridded_correction_dep_a_decode_internal(
           ctx, &msg->tropo_delay_correction)) {
     return false;
   }
+  if (((ctx->buf_len - ctx->offset) % SBP_STEC_RESIDUAL_ENCODED_LEN) != 0) {
+    return false;
+  }
   msg->n_stec_residuals =
       (uint8_t)((ctx->buf_len - ctx->offset) / SBP_STEC_RESIDUAL_ENCODED_LEN);
   for (uint8_t i = 0; i < msg->n_stec_residuals; i++) {
@@ -3905,6 +3942,9 @@ bool sbp_msg_ssr_grid_definition_dep_a_decode_internal(
   if (!sbp_grid_definition_header_dep_a_decode_internal(ctx, &msg->header)) {
     return false;
   }
+  if (((ctx->buf_len - ctx->offset) % SBP_ENCODED_LEN_U8) != 0) {
+    return false;
+  }
   msg->n_rle_list =
       (uint8_t)((ctx->buf_len - ctx->offset) / SBP_ENCODED_LEN_U8);
   for (uint8_t i = 0; i < msg->n_rle_list; i++) {
@@ -4163,6 +4203,9 @@ bool sbp_msg_ssr_orbit_clock_bounds_decode_internal(
   if (!sbp_u8_decode(ctx, &msg->n_sats)) {
     return false;
   }
+  if (((ctx->buf_len - ctx->offset) % SBP_ORBIT_CLOCK_BOUND_ENCODED_LEN) != 0) {
+    return false;
+  }
   msg->n_sats = (uint8_t)((ctx->buf_len - ctx->offset) /
                           SBP_ORBIT_CLOCK_BOUND_ENCODED_LEN);
   for (uint8_t i = 0; i < msg->n_sats; i++) {
@@ -4408,6 +4451,10 @@ bool sbp_msg_ssr_code_phase_biases_bounds_decode_internal(
   if (!sbp_u8_decode(ctx, &msg->n_sats_signals)) {
     return false;
   }
+  if (((ctx->buf_len - ctx->offset) %
+       SBP_CODE_PHASE_BIASES_SAT_SIG_ENCODED_LEN) != 0) {
+    return false;
+  }
   msg->n_sats_signals = (uint8_t)((ctx->buf_len - ctx->offset) /
                                   SBP_CODE_PHASE_BIASES_SAT_SIG_ENCODED_LEN);
   for (uint8_t i = 0; i < msg->n_sats_signals; i++) {
diff --git a/c/src/v4/system.c b/c/src/v4/system.c
index c007f3cd40..4a80719663 100644
--- a/c/src/v4/system.c
+++ b/c/src/v4/system.c
@@ -509,6 +509,9 @@ bool sbp_msg_status_report_decode_internal(sbp_decode_ctx_t *ctx,
   if (!sbp_u32_decode(ctx, &msg->uptime)) {
     return false;
   }
+  if (((ctx->buf_len - ctx->offset) % SBP_SUB_SYSTEM_REPORT_ENCODED_LEN) != 0) {
+    return false;
+  }
   msg->n_status = (uint8_t)((ctx->buf_len - ctx->offset) /
                             SBP_SUB_SYSTEM_REPORT_ENCODED_LEN);
   for (uint8_t i = 0; i < msg->n_status; i++) {
@@ -702,6 +705,10 @@ bool sbp_msg_status_journal_decode_internal(sbp_decode_ctx_t *ctx,
   if (!sbp_u8_decode(ctx, &msg->sequence_descriptor)) {
     return false;
   }
+  if (((ctx->buf_len - ctx->offset) % SBP_STATUS_JOURNAL_ITEM_ENCODED_LEN) !=
+      0) {
+    return false;
+  }
   msg->n_journal = (uint8_t)((ctx->buf_len - ctx->offset) /
                              SBP_STATUS_JOURNAL_ITEM_ENCODED_LEN);
   for (uint8_t i = 0; i < msg->n_journal; i++) {
@@ -1748,6 +1755,9 @@ bool sbp_msg_group_meta_decode_internal(sbp_decode_ctx_t *ctx,
   if (!sbp_u8_decode(ctx, &msg->n_group_msgs)) {
     return false;
   }
+  if (((ctx->buf_len - ctx->offset) % SBP_ENCODED_LEN_U16) != 0) {
+    return false;
+  }
   msg->n_group_msgs =
       (uint8_t)((ctx->buf_len - ctx->offset) / SBP_ENCODED_LEN_U16);
   for (uint8_t i = 0; i < msg->n_group_msgs; i++) {
diff --git a/c/src/v4/telemetry.c b/c/src/v4/telemetry.c
index 6f48ba4156..7acb192e73 100644
--- a/c/src/v4/telemetry.c
+++ b/c/src/v4/telemetry.c
@@ -212,6 +212,9 @@ bool sbp_msg_tel_sv_decode_internal(sbp_decode_ctx_t *ctx,
   if (!sbp_u8_decode(ctx, &msg->origin_flags)) {
     return false;
   }
+  if (((ctx->buf_len - ctx->offset) % SBP_TELEMETRY_SV_ENCODED_LEN) != 0) {
+    return false;
+  }
   msg->n_sv_tel =
       (uint8_t)((ctx->buf_len - ctx->offset) / SBP_TELEMETRY_SV_ENCODED_LEN);
   for (uint8_t i = 0; i < msg->n_sv_tel; i++) {
diff --git a/c/src/v4/tracking.c b/c/src/v4/tracking.c
index df2822c079..deb8c042ab 100644
--- a/c/src/v4/tracking.c
+++ b/c/src/v4/tracking.c
@@ -712,6 +712,10 @@ s8 sbp_msg_tracking_state_encode(uint8_t *buf, uint8_t len, uint8_t *n_written,
 
 bool sbp_msg_tracking_state_decode_internal(sbp_decode_ctx_t *ctx,
                                             sbp_msg_tracking_state_t *msg) {
+  if (((ctx->buf_len - ctx->offset) % SBP_TRACKING_CHANNEL_STATE_ENCODED_LEN) !=
+      0) {
+    return false;
+  }
   msg->n_states = (uint8_t)((ctx->buf_len - ctx->offset) /
                             SBP_TRACKING_CHANNEL_STATE_ENCODED_LEN);
   for (uint8_t i = 0; i < msg->n_states; i++) {
@@ -862,6 +866,9 @@ s8 sbp_msg_measurement_state_encode(uint8_t *buf, uint8_t len,
 
 bool sbp_msg_measurement_state_decode_internal(
     sbp_decode_ctx_t *ctx, sbp_msg_measurement_state_t *msg) {
+  if (((ctx->buf_len - ctx->offset) % SBP_MEASUREMENT_STATE_ENCODED_LEN) != 0) {
+    return false;
+  }
   msg->n_states = (uint8_t)((ctx->buf_len - ctx->offset) /
                             SBP_MEASUREMENT_STATE_ENCODED_LEN);
   for (uint8_t i = 0; i < msg->n_states; i++) {
@@ -1478,6 +1485,10 @@ s8 sbp_msg_tracking_state_dep_a_encode(
 
 bool sbp_msg_tracking_state_dep_a_decode_internal(
     sbp_decode_ctx_t *ctx, sbp_msg_tracking_state_dep_a_t *msg) {
+  if (((ctx->buf_len - ctx->offset) %
+       SBP_TRACKING_CHANNEL_STATE_DEP_A_ENCODED_LEN) != 0) {
+    return false;
+  }
   msg->n_states = (uint8_t)((ctx->buf_len - ctx->offset) /
                             SBP_TRACKING_CHANNEL_STATE_DEP_A_ENCODED_LEN);
   for (uint8_t i = 0; i < msg->n_states; i++) {
@@ -1644,6 +1655,10 @@ s8 sbp_msg_tracking_state_dep_b_encode(
 
 bool sbp_msg_tracking_state_dep_b_decode_internal(
     sbp_decode_ctx_t *ctx, sbp_msg_tracking_state_dep_b_t *msg) {
+  if (((ctx->buf_len - ctx->offset) %
+       SBP_TRACKING_CHANNEL_STATE_DEP_B_ENCODED_LEN) != 0) {
+    return false;
+  }
   msg->n_states = (uint8_t)((ctx->buf_len - ctx->offset) /
                             SBP_TRACKING_CHANNEL_STATE_DEP_B_ENCODED_LEN);
   for (uint8_t i = 0; i < msg->n_states; i++) {
diff --git a/c/src/v4/user.c b/c/src/v4/user.c
index a761167a12..b56f5e0677 100644
--- a/c/src/v4/user.c
+++ b/c/src/v4/user.c
@@ -43,6 +43,9 @@ s8 sbp_msg_user_data_encode(uint8_t *buf, uint8_t len, uint8_t *n_written,
 
 bool sbp_msg_user_data_decode_internal(sbp_decode_ctx_t *ctx,
                                        sbp_msg_user_data_t *msg) {
+  if (((ctx->buf_len - ctx->offset) % SBP_ENCODED_LEN_U8) != 0) {
+    return false;
+  }
   msg->n_contents =
       (uint8_t)((ctx->buf_len - ctx->offset) / SBP_ENCODED_LEN_U8);
   for (uint8_t i = 0; i < msg->n_contents; i++) {
diff --git a/generator/sbpg/targets/resources/c/src/sbp_messages_template.c b/generator/sbpg/targets/resources/c/src/sbp_messages_template.c
index 671261d912..4aa5e51c9c 100644
--- a/generator/sbpg/targets/resources/c/src/sbp_messages_template.c
+++ b/generator/sbpg/targets/resources/c/src/sbp_messages_template.c
@@ -218,6 +218,9 @@ bool (((m.internal_decode_fn)))(sbp_decode_ctx_t *ctx, (((m.type_name))) *msg)
     if (!(((f.decode_fn)))(ctx, &(((field)))[i])) { return false; }
   }
   ((*- elif f.packing == "variable-array" *))
+    if ( ((ctx->buf_len - ctx->offset) % (((f.encoded_len_macro)))) != 0) {
+      return false;
+    }
     msg->(((f.size_fn))) = (uint8_t)((ctx->buf_len - ctx->offset) / (((f.encoded_len_macro))));
   for (uint8_t i = 0; i < msg->(((f.size_fn))); i++) {
     if (!(((f.decode_fn)))(ctx, &(((field)))[i])) { return false; }