diff --git a/Arduino-Chunithm-Reader.ino b/Arduino-Chunithm-Reader.ino
new file mode 100644
index 0000000..647f96f
--- /dev/null
+++ b/Arduino-Chunithm-Reader.ino
@@ -0,0 +1,119 @@
+#include "cmd.h"
+
+void SerialCheck() {
+  switch (packet_read()) {
+    case SG_NFC_CMD_RESET:
+      sg_nfc_cmd_reset();
+      break;
+    case SG_NFC_CMD_GET_FW_VERSION:
+      sg_nfc_cmd_get_fw_version();
+      break;
+    case SG_NFC_CMD_GET_HW_VERSION:
+      sg_nfc_cmd_get_hw_version();
+      break;
+    case SG_NFC_CMD_POLL:
+      sg_nfc_cmd_poll();
+      break;
+    case SG_NFC_CMD_MIFARE_READ_BLOCK:
+      sg_nfc_cmd_mifare_read_block();
+      break;
+    case SG_NFC_CMD_FELICA_ENCAP:
+      sg_nfc_cmd_felica_encap();
+      break;
+    case SG_NFC_CMD_MIFARE_AUTHENTICATE:
+      sg_res_init();
+      break;
+    case SG_NFC_CMD_MIFARE_SELECT_TAG:
+      sg_res_init();
+      break;
+    case SG_NFC_CMD_MIFARE_SET_KEY_AIME:
+      sg_nfc_cmd_mifare_set_key_aime();
+      break;
+    case SG_NFC_CMD_MIFARE_SET_KEY_BANA:
+      sg_res_init();
+      break;
+    case SG_NFC_CMD_RADIO_ON:
+      sg_nfc_cmd_radio_on();
+      break;
+    case SG_NFC_CMD_RADIO_OFF:
+      sg_nfc_cmd_radio_off();
+      break;
+    case SG_RGB_CMD_RESET:
+      sg_led_cmd_reset();
+      break;
+    case SG_RGB_CMD_GET_INFO:
+      sg_led_cmd_get_info();
+      break;
+    case SG_RGB_CMD_SET_COLOR:
+      sg_led_cmd_set_color();
+      break;
+  }
+}
+
+void setup() {
+  SerialUSB.begin(38400);
+  SerialUSB.setTimeout(0);
+  FastLED.addLeds<WS2812B, DATA_PIN, GRB>(leds, NUM_LEDS);
+  nfc.begin();
+  nfc.SAMConfig();
+  memset(&req, 0, sizeof(req.bytes));
+  memset(&res, 0, sizeof(res.bytes));
+}
+
+void loop() {
+  SerialCheck();
+  packet_write();
+}
+
+static uint8_t packet_read() {
+  uint8_t len, r, checksum;
+  bool escape = false;
+  while (SerialUSB.available()) {
+    r = SerialUSB.read();
+    if (r == 0xE0) {
+      req.frame_len = 0xFF;
+      continue;
+    }
+    if (req.frame_len == 0xFF) {
+      req.frame_len = r;
+      len = 1;
+      checksum = r;
+      continue;
+    }
+    if (r == 0xD0) {
+      escape = true;
+      continue;
+    }
+    if (escape) {
+      r++;
+      escape = false;
+    }
+    if (len == req.frame_len && checksum == r) {
+      return req.cmd;
+    }
+    req.bytes[len++] = r;
+    checksum += r;
+  }
+  return 0;
+}
+
+static void packet_write() {
+  if (res.cmd == 0)
+    return;
+  uint8_t checksum = 0;
+  SerialUSB.write(0xE0);
+  for (uint8_t i = 0; i < res.frame_len; i++) {
+    uint8_t w = res.bytes[i];
+    checksum += w;
+    if (SerialUSB.availableForWrite() < 2)
+      return;
+    if (w == 0xE0 || w == 0xD0) {
+      SerialUSB.write(0xD0);
+      SerialUSB.write(--w);
+    } else {
+      SerialUSB.write(w);
+    }
+  }
+  SerialUSB.write(checksum);
+  res.cmd = 0;
+}
diff --git a/card.txt b/card.txt
new file mode 100644
index 0000000..4c52079
--- /dev/null
+++ b/card.txt
@@ -0,0 +1,14 @@
+E0 [05] 00 [7D] [42] 00 [C4] //读卡
+E0 [19] 00 [7D] [42] 00 13 01 20 10 [ 8 byte IDm ] [ 8 byte PMm ] [  ]
+
+
+E0 [13] 00 [80] [71] 0E [ 8 byte IDm ] 06 [00] FF FF 01 0F [  ]
+E0 [1A] 00 [80] [71] 00 [14] 14 01 [ 8 byte IDm ] [ 8 byte PMm ] 00 00 [  ]
+
+
+E0 [17] 00 [81] [71] 12 [ 8 byte IDm ] 0A [0C] [ 8 byte IDm ] [  ]
+E0 [13] 00 [81] [71] 00 [0D] 0D 0D [ 8 byte IDm ] 01 00 00 [  ]
+
+
+E0 [18] 00 [82] [71] 13 [ 8 byte IDm ] 0B [A4] [ 8 byte IDm ] 00 [  ]
+E0 [11] 00 [82] [71] 00 [0B] 0B A5 [ 8 byte IDm ] 00 [  ]
diff --git a/chunihook.dll b/chunihook.dll
new file mode 100644
index 0000000..6a0b29e
Binary files /dev/null and b/chunihook.dll differ
diff --git a/cmd.h b/cmd.h
new file mode 100644
index 0000000..d6066a3
--- /dev/null
+++ b/cmd.h
@@ -0,0 +1,239 @@
+#include "FastLED.h"
+#define NUM_LEDS 6
+#define DATA_PIN A3
+#define BRI 50
+CRGB leds[NUM_LEDS];
+
+#include "Adafruit_PN532.h"
+#define PN532_IRQ   (4)
+Adafruit_PN532 nfc(PN532_IRQ, 16);
+boolean readerDisabled = false;
+
+uint8_t AimeKey[6];
+uint8_t MifareKey[6] = {0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF};
+
+enum {
+  SG_NFC_CMD_GET_FW_VERSION = 0x30,//获取FW版本
+  SG_NFC_CMD_GET_HW_VERSION = 0x32,//获取HW版本
+  SG_NFC_CMD_RADIO_ON = 0x40,//打开读卡器天线
+  SG_NFC_CMD_RADIO_OFF = 0x41,//关闭读卡器天线
+  SG_NFC_CMD_POLL = 0x42,//发送卡号
+  SG_NFC_CMD_MIFARE_SELECT_TAG = 0x43,
+  SG_NFC_CMD_MIFARE_SET_KEY_BANA = 0x50,
+  SG_NFC_CMD_MIFARE_READ_BLOCK = 0x52,
+  SG_NFC_CMD_MIFARE_SET_KEY_AIME = 0x54,
+  SG_NFC_CMD_MIFARE_AUTHENTICATE = 0x55,
+  SG_NFC_CMD_RESET = 0x62,//重置读卡器
+  SG_NFC_CMD_FELICA_ENCAP = 0x71,
+  SG_RGB_CMD_SET_COLOR = 0x81,//LED颜色设置
+  SG_RGB_CMD_RESET = 0xF5,//LED重置
+  SG_RGB_CMD_GET_INFO = 0xF0,//LED信息获取
+  FELICA_CMD_POLL             = 0x00,//ENCAP用
+  FELICA_CMD_GET_SYSTEM_CODE  = 0x0c,
+  FELICA_CMD_NDA_A4           = 0xa4,
+};
+
+typedef union packet_req {
+  uint8_t bytes[256];
+  struct {
+    uint8_t frame_len;
+    uint8_t addr;
+    uint8_t seq_no;
+    uint8_t cmd;
+    uint8_t payload_len;
+    union {
+      uint8_t key[6];// sg_nfc_req_mifare_set_key
+      struct {// sg_nfc_cmd_mifare_read_block
+        uint8_t uid[4];
+        uint8_t block_no;
+      };
+      struct {// sg_nfc_req_felica_encap
+        uint8_t IDm[8];
+        uint8_t encap_len;
+        uint8_t code;
+        uint8_t felica_payload[241];
+      };
+      uint8_t color_payload[3];//sg_led_req_set_color
+    };
+  };
+
+} packet_req_t;
+
+typedef union packet_res {
+  uint8_t bytes[256];
+  struct {
+    uint8_t frame_len;
+    uint8_t addr;
+    uint8_t seq_no;
+    uint8_t cmd;
+    uint8_t status;
+    uint8_t payload_len;
+    union {
+      char version[23];// sg_nfc_res_get_fw_version,sg_nfc_res_get_hw_version
+      struct {// sg_nfc_res_poll
+        uint8_t count;
+        uint8_t type;
+        uint8_t id_len;
+        union {
+          uint8_t uid[4];
+          uint8_t IDPM[16];
+        };
+      };
+      uint8_t block[16];// sg_nfc_res_mifare_read_block
+      struct {// sg_nfc_res_felica_encap
+        uint8_t encap_len;
+        uint8_t code;
+        uint8_t IDm[8];
+        union {
+          struct {
+            uint8_t PMm[8];
+            uint8_t system_code[2];
+          };
+          uint8_t felica_payload[241];
+        };
+      };
+      uint8_t reset_payload;  //sg_led_res_reset
+      uint8_t info_payload[9]; //sg_led_res_get_info
+    };
+  };
+} packet_res_t;
+
+static packet_req_t req;
+static packet_res_t res;
+
+static void sg_res_init(uint8_t payload_len = 0) { //初始化模板
+  res.frame_len = 6 + payload_len;
+  res.addr = req.addr;
+  res.seq_no = req.seq_no;
+  res.cmd = req.cmd;
+  res.status = 0;
+  res.payload_len = payload_len;
+}
+
+static void sg_nfc_cmd_reset() {//重置读卡器
+  sg_res_init();
+  res.status = 3;
+  readerDisabled = true;
+}
+
+static void sg_nfc_cmd_get_fw_version() {
+  sg_res_init(sizeof(res.version));
+  memcpy(res.version, "TN32MSEC003S F/W Ver1.2E", sizeof(res.version));
+}
+
+static void sg_nfc_cmd_get_hw_version() {
+  sg_res_init(sizeof(res.version));
+  memcpy(res.version, "TN32MSEC003S H/W Ver3.0J", sizeof(res.version));
+}
+
+static void sg_nfc_cmd_mifare_set_key_aime() {
+  sg_res_init();
+  memcpy(req.key, AimeKey, sizeof(AimeKey));
+}
+
+static void sg_led_cmd_reset() {
+  sg_res_init(sizeof(res.reset_payload));
+  res.reset_payload = 0;
+  fill_solid(leds, NUM_LEDS, 0x000000);
+  FastLED[0].show(leds, NUM_LEDS, BRI);
+}
+
+static void sg_led_cmd_get_info() {
+  sg_res_init(sizeof(res.info_payload));
+  static uint8_t info[] = {'1', '5', '0', '8', '4', 0xFF, 0x10, 0x00, 0x12};
+  memcpy(res.info_payload, info, 9);
+}
+
+static void sg_led_cmd_set_color() {
+  uint8_t r = req.color_payload[0];
+  uint8_t g = req.color_payload[1];
+  uint8_t b = req.color_payload[2];
+  fill_solid(leds, NUM_LEDS, CRGB(r, g, b));
+  FastLED[0].show(leds, NUM_LEDS, BRI);
+}
+
+static void sg_nfc_cmd_radio_on() {
+  sg_res_init();
+  if (!readerDisabled) {
+    return;
+  }
+  nfc.startPassiveTargetIDDetection(PN532_MIFARE_ISO14443A);
+  readerDisabled = false;
+}
+
+static void sg_nfc_cmd_radio_off() {
+  sg_res_init();
+  readerDisabled = true;
+}
+
+static void sg_nfc_cmd_poll() { //卡号发送
+  uint8_t uid[4];
+  uint8_t t;
+  //读aime（实验性）
+  nfc.startPassiveTargetIDDetection(PN532_MIFARE_ISO14443A);
+  delay(10);
+  if (!digitalRead(PN532_IRQ)) {
+    nfc.readDetectedPassiveTargetID(uid, &t);
+    if (nfc.mifareclassic_AuthenticateBlock(uid, t, 1, MIFARE_CMD_AUTH_B, AimeKey)) { //aime
+      res.type = 0x10;
+      res.id_len = t;
+      memcpy(res.uid, uid, t);//默认ID为0x01020304
+      sg_res_init(7);
+      res.count = 1;
+      return;
+    }
+  }
+  //读普通mifare当作felica
+  nfc.startPassiveTargetIDDetection(PN532_MIFARE_ISO14443A);
+  delay(10);
+  if (!digitalRead(PN532_IRQ)) {
+    nfc.readDetectedPassiveTargetID(uid, &t);
+    if (nfc.mifareclassic_AuthenticateBlock(uid, t, 1, MIFARE_CMD_AUTH_A, MifareKey)) {
+      if (nfc.mifareclassic_ReadDataBlock(1, res.IDPM)) {//此处略过了IDm和PMm的分别读取
+        res.type = 0x20;
+        res.id_len = sizeof(res.IDPM);
+        sg_res_init(19);//count,type,id_len,IDm,PMm
+        res.count = 1;
+        return;
+      }
+    }
+  }
+  sg_res_init(1);
+  res.count = 0;
+}
+
+static void sg_nfc_cmd_mifare_read_block() {
+  if (req.block_no > 3)
+    return;
+  sg_res_init(sizeof(res.block));
+  if (nfc.mifareclassic_AuthenticateBlock(req.uid, 4, req.block_no, MIFARE_CMD_AUTH_B, AimeKey)) {
+    if (nfc.mifareclassic_ReadDataBlock(req.block_no, res.block)) {
+      return;
+    }
+  }
+  sg_res_init();
+}
+
+static void sg_nfc_cmd_felica_encap() {
+  uint8_t code = req.code;
+  res.code = code + 1;
+  memcpy(res.IDm, req.IDm, sizeof(req.IDm));
+  switch (code) {
+    case FELICA_CMD_POLL:
+      sg_res_init(0x14);
+      res.system_code[0] = 0x00;
+      res.system_code[1] = 0x00;
+      break;
+    case FELICA_CMD_GET_SYSTEM_CODE:
+      sg_res_init(0x0D);
+      res.felica_payload[0] = 0x01;
+      res.felica_payload[1] = 0x00;
+      res.felica_payload[2] = 0x00;
+      break;
+    case FELICA_CMD_NDA_A4:
+      sg_res_init(0x0B);
+      res.felica_payload[0] = 0x00;
+      break;
+  }
+  res.encap_len = res.payload_len;
+}
diff --git a/nfc.txt b/nfc.txt
new file mode 100644
index 0000000..3e47c40
--- /dev/null
+++ b/nfc.txt
@@ -0,0 +1,244 @@
+N.B. Quoted strings are NOT NUL-terminated unless otherwise noted.
+Useful reading: https://www.nxp.com/docs/en/data-sheet/MF1S50YYX_V1.pdf
+
+(AiMe branded cards are Mifare Classic cards. Other technologies exist though)
+
+Summary
+-------
+
+Hardware:
+    Assembly connector:
+        5V Host in
+        Tx;Rx;GND Host RS232 in
+        Tx;Rx;GND Daisy-chain out
+    Main board (probably LED controller):
+        Silk "837-15084"
+        CN1: Host 5V power in, ?V NFC-sub power out
+        CN2: Host RS232 Tx;Rx;GND in, NFC-sub Tx;Rx out
+        CN3: LED-Sub power and data(?) out
+        DIPSW1: Set to hex nibble 8.
+        Contains ADM3222 RS232 transceiver IC
+        Contains ATMega32 MCU
+    NFC subboard:
+        Sticker: Model "TN32MSEC003S"
+        CN1: ?V power and Tx;Rx;GND in, Tx;Rx;GND ass'y CN daisy out.
+        DIPSW1: Set to hex nibble 0.
+        Contains ATmega168 MCU
+        Contains ADM3202A RS232 transceiver IC
+        Contains shielded RF circuit
+        Entire non-ground-plane PCB area is visible through the chassis
+        torx screws lol
+    LED subboard:
+        Silk: "837-15120"
+        CN1: ?V power and Tx;Rx;GND in.
+        Five RGB LEDs and a bunch of resistors
+        No visible logic ICs..?
+        No DIPSW.
+
+JVS framing:
+    E0 sync
+    D0 escape (+1 to unescape)
+    Checksum is sum of bytes after unescaping
+
+Frame header:
+    Frame length (including length byte itself)
+    Address
+    Sequence no, hopefully loops before hitting esc byte...
+    Command byte
+
+Bus addressing:
+    Low nibble set using DIPSWs
+    High nibble ???
+    Daisy chaining mechanism unknown (RS232 wires probably multi-tap)
+
+Startup
+-------
+
+Addr 00 Command 62:
+    Req:
+        00  Payload length
+    Resp:
+        00  Status byte
+        00  Payload length
+    Description:
+        Unknown. Reset?
+
+Addr 00 Command 30:
+    Req:
+        00  Payload length
+    Resp:
+        00  Status byte
+        17  Payload length
+        ..  "TN32MSEC003S F/W Ver1.2E"
+    Description:
+        Get firmware version
+
+Addr 00 Command 32:
+    Req:
+        00  Payload length
+    Resp:
+        00  Status byte
+        17  Payload length
+        ..  "TN32MSEC003S H/W Ver3.0J"
+    Description:
+        Get hardware version
+
+Addr 08 Command f5:
+    Req:
+        00  Payload length
+    Resp:
+        00  Status byte
+        00  Payload length
+    Description:
+        LED sub-board reset.
+        Won't accept LED commands until you do this.
+
+Addr 08 Command f0:
+    Req:
+        00  Payload length
+    Resp:
+        00  Status byte
+        09  Payload length
+        ..  "15084" (part nr for LED board)
+        FF  ??
+        11  ??
+        00  ??
+        12  ??
+    Description:
+        Get board "info"
+
+Addr 00 Command 54:
+    Req:
+        06  Payload length
+        57  'W'
+        43  'C'
+        43  'C'
+        46  'F'
+        76  'v'
+        32  '2'
+    Resp:
+        00  Status byte?
+        00  ??
+    Description:
+        Set Mifare KeyA.
+        "WCCF" might refer this this SEGA arcade game:
+        https://en.wikipedia.org/wiki/World_Club_Champion_Football
+        It's quite old and has AiMe readers, maybe where they first appeared?
+
+Addr 00 Command 50:
+    Req:
+        06  Payload length
+        60  ??
+        90  ??
+        D0  ?? (This is escaped of course)
+        06  ??
+        32  ??
+        F5  ??
+    Resp:
+        00  Status byte
+        00  Payload length
+    Description:
+        Possibly Mifare KeyB.
+
+Polling
+-------
+
+Addr 00 Command 40:
+    Req:
+        01  Payload length
+        03  ??
+    Resp:
+        00  Status byte
+        00  Payload length
+    Description:
+        Poll some other NFC technology?
+
+Addr 00 Command 42:
+    Req:
+        00  Payload length
+    Resp if no MiFare card:
+        00  Status byte
+        01  Payload length
+        00  (represents nothing i guess)
+    Resp if MiFare card:
+        00  Status byte?
+        07  Payload length
+                01  Chunk length?
+                10  ?? Block size maybe?
+                04  Chunk length?
+                ..  Mifare UID, four bytes.
+    Description:
+        Check for Mifare card presence?
+
+Addr 00 Command 41:
+    Req:
+        00  Payload length
+    Resp:
+        00  Status byte
+        00  Payload length
+    Description:
+        Unknown. Poll some other NFC technology?
+
+Card read
+---------
+
+Addr 00 Command 43:
+    Req:
+        04  Payload length
+        ..  Mifare UID, four bytes.
+    Resp:
+        00  Status byte
+        00  Payload length
+    Description:
+        Select MiFare by UID?
+
+Addr 00 Command 55:
+    Req:
+        05  Payload length
+        ..  Mifare UID, four bytes.
+        03  ??
+    Resp:
+        00  Status byte
+        00  Payload length
+    Description:
+        Unknown.
+        Block 3 on a Mifare sector contains keys and an access control list.
+        It is generally not accessed directly (unless being provisioned?)
+
+Addr 00 Command 52:
+    Req:
+        05  Payload length
+        ..  Mifare UID, four bytes.
+        ..  Block number, 1 or 2.
+    Resp for Block 1:
+        00  Status byte
+        10  Payload length (1 block)
+        ..  "SBSD"
+            00 00 00 00
+            00 00 00 00
+            00 4E C6 22
+    Resp for Block 2:
+        00  Status byte
+        10  Payload length (1 block)
+        ..  00 00 00 00 00 00 xx xx
+            xx xx xx xx xx xx xx xx
+    Description:
+        Probably reads blocks 1 and 2 from Mifare sector 0.
+        Block 0 contains the "vendor information" and UID.
+        Block 1 contents are unknown, probably AiMe DB info.
+        Block 2 last 10 bytes hex are printed on the card ("local unique id").
+        (Block 3 contains encryption keys so is not allowed to be read)
+
+LED
+---
+
+Addr 08 Command 81:
+    Req:
+        03  Payload length
+        ff  Red intensity
+        ff  Green intensity
+        ff  Blue intensity
+    Resp:
+        None! Command is not acknowledged
+    Description:
+        Set LED color
diff --git a/sg-cmd.c b/sg-cmd.c
new file mode 100644
index 0000000..84d00f5
--- /dev/null
+++ b/sg-cmd.c
@@ -0,0 +1,144 @@
+#include <assert.h>
+
+#include "board/sg-cmd.h"
+#include "board/sg-frame.h"
+
+#include "hook/iobuf.h"
+
+#include "util/dprintf.h"
+
+union sg_req_any {
+    struct sg_req_header req;
+    uint8_t bytes[256];
+};
+
+union sg_res_any {
+    struct sg_res_header res;
+    uint8_t bytes[256];
+};
+
+static HRESULT sg_req_validate(const void *ptr, size_t nbytes);
+
+static void sg_res_error(
+        struct sg_res_header *res,
+        const struct sg_req_header *req);
+
+static HRESULT sg_req_validate(const void *ptr, size_t nbytes)
+{
+    const struct sg_req_header *req;
+    size_t payload_len;
+
+    assert(ptr != NULL);
+
+    if (nbytes < sizeof(*req)) {
+        dprintf("SG Cmd: Request header truncated\n");
+
+        return E_FAIL;
+    }
+
+    req = ptr;
+
+    if (req->hdr.frame_len != nbytes) {
+        dprintf("SG Cmd: Frame length mismatch: got %i exp %i\n",
+                req->hdr.frame_len,
+                (int) nbytes);
+
+        return E_FAIL;
+    }
+
+    payload_len = req->hdr.frame_len - sizeof(*req);
+
+    if (req->payload_len != payload_len) {
+        dprintf("SG Cmd: Payload length mismatch: got %i exp %i\n",
+                req->payload_len,
+                (int) payload_len);
+
+        return E_FAIL;
+    }
+
+    return S_OK;
+}
+
+void sg_req_transact(
+        struct iobuf *res_frame,
+        const uint8_t *req_bytes,
+        size_t req_nbytes,
+        sg_dispatch_fn_t dispatch,
+        void *ctx)
+{
+    printf("req: ");
+    for (uint8_t i = 0; i < req_nbytes; i++)
+        printf("%02X ", req_bytes[i]);
+    printf("\n");
+
+    struct iobuf req_span;
+    union sg_req_any req;
+    union sg_res_any res;
+    HRESULT hr;
+
+    assert(res_frame != NULL);
+    assert(req_bytes != NULL);
+    assert(dispatch != NULL);
+
+    req_span.bytes = req.bytes;
+    req_span.nbytes = sizeof(req.bytes);
+    req_span.pos = 0;
+
+    hr = sg_frame_decode(&req_span, req_bytes, req_nbytes);
+
+    if (FAILED(hr)) {
+        return;
+    }
+
+    hr = sg_req_validate(req.bytes, req_span.pos);
+
+    if (FAILED(hr)) {
+        return;
+    }
+
+    hr = dispatch(ctx, &req, &res);
+
+    if (hr != S_FALSE) {
+        if (FAILED(hr)) {
+            sg_res_error(&res.res, &req.req);
+        }
+
+        sg_frame_encode(res_frame, res.bytes, res.res.hdr.frame_len);
+        
+         printf("res: ");
+        for (uint8_t i = 0; i < res_frame->pos; i++)
+            printf("%02X ", res_frame->bytes[i]);
+        printf("\n");
+    }
+}
+
+void sg_res_init(
+        struct sg_res_header *res,
+        const struct sg_req_header *req,
+        size_t payload_len)
+{
+    assert(res != NULL);
+    assert(req != NULL);
+
+    res->hdr.frame_len = sizeof(*res) + payload_len;
+    res->hdr.addr = req->hdr.addr;
+    res->hdr.seq_no = req->hdr.seq_no;
+    res->hdr.cmd = req->hdr.cmd;
+    res->status = 0;
+    res->payload_len = payload_len;
+}
+
+static void sg_res_error(
+        struct sg_res_header *res,
+        const struct sg_req_header *req)
+{
+    assert(res != NULL);
+    assert(req != NULL);
+
+    res->hdr.frame_len = sizeof(*res);
+    res->hdr.addr = req->hdr.addr;
+    res->hdr.seq_no = req->hdr.seq_no;
+    res->hdr.cmd = req->hdr.cmd;
+    res->status = 1;
+    res->payload_len = 0;
+}