From e70c24771aaadc079be3c7d6324d50960289b9d7 Mon Sep 17 00:00:00 2001
From: sp2xdev <127630192+sp2xdev@users.noreply.github.com>
Date: Sat, 11 Jan 2025 20:32:30 -0800
Subject: [PATCH] Updated Known issues (markdown)

---
 Known-issues.md | 14 ++++++++++++--
 1 file changed, 12 insertions(+), 2 deletions(-)

diff --git a/Known-issues.md b/Known-issues.md
index 3740161..3acc283 100644
--- a/Known-issues.md
+++ b/Known-issues.md
@@ -283,11 +283,21 @@ Note that SpiceCompanion apps are not part of the spice2x project (not forked).
 
 ## Physical NFC Card Readers
 
+### HID SmartCard (ACR122U)
+
+> [!WARNING]  
+> ACR112U card readers are no longer recommended to purchase. Official product was discontinued years ago, and many cheap Chinese clones on Amazon and Alibaba are unable to properly read FeliCa cards.
+
 `HID Smartcard` option is intended for NFC readers with ACR112U chipset; it's coded to [their specifications](https://www.acs.com.hk/en/download-manual/419/API-ACR122U-2.04.pdf). Official driver is [here](https://www.acs.com.hk/en/driver/3/acr122u-usb-nfc-reader/); however, Windows default driver is usually sufficient.
 
-The official ACR112U product line from ACS has been discontinued years ago. Most of them being sold today online are poor knock-offs of ACS ACR122U. Unfortunately, some of these knock-offs are unable to properly read FeliCa cards. Please only purchase from well known resellers.
+As mentioned above, many clones of ACR112U fail to properly read FeliCa cards. When you place a FeliCa card on the reader, you may notice:
 
-If you have trouble finding a good ACR112U unit, you may instead want to look into DIY solutions based on cardIO HID protocol: https://rhythm-cons.wiki/other-hardware/card-readers/
+* Continuous beeping sound
+* `scard: error connecting to the card: 0x80100069` in spice2x logs
+
+... and not actually read the card contents.
+
+Instead of finding a good ACR112U unit, you may instead want to look into DIY solutions based on cardIO HID protocol: https://rhythm-cons.wiki/other-hardware/card-readers/
 
 There is also a known bug in ACR122U logic (`scard.cpp`) when reading UID values from cards. It interprets the "success" header `90 00` as part of the UID. If your card has UID of `1234 5678` then it's read as `1234 5678 9000 0000`. This is not an issue for FeliCa as they already have full 8 bytes of UID, it's only a problem for cards with UID < 8 bytes. It's recommended that you set `-scardfix fix` for more correct behavior for non-FeliCa cards.