diff --git a/README.md b/README.md
index 71bbdab3..9ff96c5d 100644
--- a/README.md
+++ b/README.md
@@ -3,7 +3,7 @@
 <img align="right" width="425px" src="https://github.com/xssnick/props/blob/master/logoimg.png?raw=true">
 
 [![Based on TON][ton-svg]][ton]
-![Coverage](https://img.shields.io/badge/Coverage-73.4%25-brightgreen)
+![Coverage](https://img.shields.io/badge/Coverage-73.3%25-brightgreen)
 
 Golang library for interacting with TON blockchain.
 
diff --git a/ton/block.go b/ton/block.go
index d808d6ed..99da8f6a 100644
--- a/ton/block.go
+++ b/ton/block.go
@@ -211,13 +211,13 @@ func (c *APIClient) CurrentMasterchainInfo(ctx context.Context) (_ *BlockIDExt,
 	// if not sticky - id will be 0
 	nodeID := c.client.StickyNodeID(ctx)
 
-	root.curMastersLock.RLock()
+	root.curMastersLock.Lock()
 	master := root.curMasters[nodeID]
 	if master == nil {
 		master = &masterInfo{}
 		root.curMasters[nodeID] = master
 	}
-	root.curMastersLock.RUnlock()
+	root.curMastersLock.Unlock()
 
 	master.mx.Lock()
 	defer master.mx.Unlock()
diff --git a/ton/payments/types.go b/ton/payments/types.go
index beb610bd..3eaad389 100644
--- a/ton/payments/types.go
+++ b/ton/payments/types.go
@@ -101,7 +101,6 @@ type TopupBalance struct {
 
 type CooperativeClose struct {
 	_          tlb.Magic `tlb:"#5577587e"`
-	IsA        bool      `tlb:"bool"`
 	SignatureA Signature `tlb:"^"`
 	SignatureB Signature `tlb:"^"`
 	Signed     struct {