From b7f9e3c41d4f150a0306906ddc065aceed28a96f Mon Sep 17 00:00:00 2001
From: "Aaron Tulino (Aaronjamt)" <git@aaronjamt.com>
Date: Mon, 22 Dec 2025 14:11:59 -0700
Subject: [PATCH] Correct ATS in `iso14443a` Turns out, at least for HID RevE
 readers, the ATS value must specify FSC=256 or it won't read.

---
 armsrc/iso14443a.c | 1 +
 armsrc/seos.c      | 6 +-----
 2 files changed, 2 insertions(+), 5 deletions(-)

diff --git a/armsrc/iso14443a.c b/armsrc/iso14443a.c
index ae0d1a16e..e7ce4b7d9 100644
--- a/armsrc/iso14443a.c
+++ b/armsrc/iso14443a.c
@@ -1368,6 +1368,7 @@ bool SimulateIso14443aInit(uint8_t tagType, uint16_t flags, uint8_t *data,
         }
         case 12: { // HID Seos 4K card
             rATQA[0] = 0x01;
+            rATS[1] = 0x78; // FSC=256 required
             sak = 0x20;
             break;
         }
diff --git a/armsrc/seos.c b/armsrc/seos.c
index 7a6180b7e..1e37605b5 100644
--- a/armsrc/seos.c
+++ b/armsrc/seos.c
@@ -264,12 +264,8 @@ void SimulateSeos(seos_emulate_req_t *msg) {
     memcpy(data, msg->uid, msg->uid_len);
     FLAG_SET_UID_IN_DATA(flags, msg->uid_len);
 
-    // TODO: Is this required?
-    uint8_t ats[] = { 0x05, 0x78, 0x77, 0x80, 0x02 };
-    flags |= FLAG_ATS_IN_DATA;
-
     // 12 = HID Seos 4K card
-    if (SimulateIso14443aInit(12, flags, data, ats, sizeof(ats), &responses, &cuid, NULL, NULL) == false) {
+    if (SimulateIso14443aInit(12, flags, data, NULL, 0, &responses, &cuid, NULL, NULL) == false) {
         BigBuf_free_keep_EM();
         reply_ng(CMD_HF_SEOS_SIMULATE, PM3_EINIT, NULL, 0);
         return;