diff --git a/src/CNProtocol.hpp b/src/CNProtocol.hpp
index e101175..2d72ec8 100644
--- a/src/CNProtocol.hpp
+++ b/src/CNProtocol.hpp
@@ -7,7 +7,9 @@
 #include <stdint.h>
 #ifdef _WIN32
 // windows
+    #ifndef NOMINMAX
     #define NOMINMAX
+    #endif
     #define _WINSOCK_DEPRECATED_NO_WARNINGS
     #include <winsock2.h>
     #include <windows.h>
diff --git a/src/GroupManager.cpp b/src/GroupManager.cpp
index a40512e..d3902f0 100644
--- a/src/GroupManager.cpp
+++ b/src/GroupManager.cpp
@@ -147,9 +147,6 @@ void GroupManager::joinGroup(CNSocket* sock, CNPacketData* data) {
 }
 
 void GroupManager::leaveGroup(CNSocket* sock, CNPacketData* data) {
-    if (data->size != sizeof(P_CL2FE_REQ_PC_GROUP_LEAVE))
-        return; // malformed packet
-
     Player* plr = PlayerManager::getPlayer(sock);
 
     if (plr == nullptr)
diff --git a/src/NPCManager.cpp b/src/NPCManager.cpp
index 841ddf8..225fe47 100644
--- a/src/NPCManager.cpp
+++ b/src/NPCManager.cpp
@@ -351,7 +351,7 @@ void NPCManager::npcVendorTable(CNSocket* sock, CNPacketData* data) {
 
     INITSTRUCT(sP_FE2CL_REP_PC_VENDOR_TABLE_UPDATE_SUCC, resp);
 
-    for (int i = 0; i < listings.size() && i < 20; i++) { // 20 is the max
+    for (int i = 0; i < (int)listings.size() && i < 20; i++) { // 20 is the max
         sItemBase base;
         base.iID = listings[i].iID;
         base.iOpt = 0;
@@ -393,7 +393,7 @@ void NPCManager::npcVendorBuyBattery(CNSocket* sock, CNPacketData* data) {
     if (plr == nullptr)
         return;
 
-    int cost = req->Item.iOpt * 100;
+    int cost = req->Item.iOpt * 10;
     if ((req->Item.iID == 3 ? (plr->batteryW >= 9999) : (plr->batteryN >= 9999)) || plr->money < cost) { // sanity check
         INITSTRUCT(sP_FE2CL_REP_PC_VENDOR_BATTERY_BUY_FAIL, failResp);
         failResp.iErrorCode = 0;
diff --git a/src/NanoManager.cpp b/src/NanoManager.cpp
index 41b7435..2454800 100644
--- a/src/NanoManager.cpp
+++ b/src/NanoManager.cpp
@@ -702,6 +702,8 @@ void NanoManager::nanoBuff(CNSocket* sock, int16_t nanoId, int skillId, int16_t
 
     if (groupPower)
         pktCnt = leader->groupCnt;
+    else
+        leader = plr;
 
     if (!validOutVarPacket(sizeof(sP_FE2CL_NANO_SKILL_USE), pktCnt, sizeof(sSkillResult_Buff))) {
         std::cout << "[WARN] bad sP_FE2CL_NANO_SKILL_USE packet size\n";
@@ -783,6 +785,8 @@ void NanoManager::nanoUnbuff(CNSocket* sock, int32_t iCBFlag, int16_t eCharStatu
 
     if (groupPower)
         pktCnt = leader->groupCnt;
+    else
+        leader = plr;
 
     for (int i = 0; i < pktCnt; i++) {
         Player* varPlr;
@@ -813,7 +817,7 @@ void NanoManager::nanoUnbuff(CNSocket* sock, int32_t iCBFlag, int16_t eCharStatu
 
 // 0=A 1=B 2=C -1=Not found
 int NanoManager::nanoStyle(int nanoId) {
-    if (nanoId < 0 || nanoId >= NanoTable.size())
+    if (nanoId < 0 || nanoId >= (int)NanoTable.size())
         return -1;
     return NanoTable[nanoId].style;
 }