diff --git a/cli/smartcontract/smart_contract.go b/cli/smartcontract/smart_contract.go
index 292c6649c..a1575755b 100644
--- a/cli/smartcontract/smart_contract.go
+++ b/cli/smartcontract/smart_contract.go
@@ -399,8 +399,10 @@ func invokeInternal(ctx *cli.Context, signAndPush bool) error {
 	if !args.Present() {
 		return cli.NewExitError(errNoScriptHash, 1)
 	}
-	script := args[0]
-
+	script, err := util.Uint160DecodeStringLE(args[0])
+	if err != nil {
+		return cli.NewExitError(fmt.Errorf("incorrect script hash: %v", err), 1)
+	}
 	if len(args) <= 1 {
 		return cli.NewExitError(errNoMethod, 1)
 	}
@@ -510,8 +512,7 @@ func testInvokeScript(ctx *cli.Context) error {
 		return err
 	}
 
-	scriptHex := hex.EncodeToString(nefFile.Script)
-	resp, err := c.InvokeScript(scriptHex, cosigners)
+	resp, err := c.InvokeScript(nefFile.Script, cosigners)
 	if err != nil {
 		return cli.NewExitError(err, 1)
 	}
@@ -654,12 +655,17 @@ func contractDeploy(ctx *cli.Context) error {
 		return err
 	}
 
-	txScript, sysfee, err := request.CreateDeploymentScript(nefFile.Script, m)
+	txScript, err := request.CreateDeploymentScript(nefFile.Script, m)
 	if err != nil {
 		return cli.NewExitError(fmt.Errorf("failed to create deployment script: %v", err), 1)
 	}
+	// It doesn't require any cosigners.
+	invRes, err := c.InvokeScript(txScript, nil)
+	if err != nil {
+		return cli.NewExitError(fmt.Errorf("failed to test-invoke deployment script: %v", err), 1)
+	}
 
-	txHash, err := c.SignAndPushInvocationTx(txScript, acc, sysfee, gas)
+	txHash, err := c.SignAndPushInvocationTx(txScript, acc, invRes.GasConsumed, gas)
 	if err != nil {
 		return cli.NewExitError(fmt.Errorf("failed to push invocation tx: %v", err), 1)
 	}
diff --git a/pkg/rpc/client/nep5.go b/pkg/rpc/client/nep5.go
index 651d4e12d..b8b84722d 100644
--- a/pkg/rpc/client/nep5.go
+++ b/pkg/rpc/client/nep5.go
@@ -1,7 +1,6 @@
 package client
 
 import (
-	"encoding/hex"
 	"errors"
 	"fmt"
 
@@ -25,7 +24,7 @@ var (
 
 // NEP5Decimals invokes `decimals` NEP5 method on a specified contract.
 func (c *Client) NEP5Decimals(tokenHash util.Uint160) (int64, error) {
-	result, err := c.InvokeFunction(tokenHash.StringLE(), "decimals", []smartcontract.Parameter{}, nil)
+	result, err := c.InvokeFunction(tokenHash, "decimals", []smartcontract.Parameter{}, nil)
 	if err != nil {
 		return 0, err
 	} else if result.State != "HALT" || len(result.Stack) == 0 {
@@ -37,7 +36,7 @@ func (c *Client) NEP5Decimals(tokenHash util.Uint160) (int64, error) {
 
 // NEP5Name invokes `name` NEP5 method on a specified contract.
 func (c *Client) NEP5Name(tokenHash util.Uint160) (string, error) {
-	result, err := c.InvokeFunction(tokenHash.StringLE(), "name", []smartcontract.Parameter{}, nil)
+	result, err := c.InvokeFunction(tokenHash, "name", []smartcontract.Parameter{}, nil)
 	if err != nil {
 		return "", err
 	} else if result.State != "HALT" || len(result.Stack) == 0 {
@@ -49,7 +48,7 @@ func (c *Client) NEP5Name(tokenHash util.Uint160) (string, error) {
 
 // NEP5Symbol invokes `symbol` NEP5 method on a specified contract.
 func (c *Client) NEP5Symbol(tokenHash util.Uint160) (string, error) {
-	result, err := c.InvokeFunction(tokenHash.StringLE(), "symbol", []smartcontract.Parameter{}, nil)
+	result, err := c.InvokeFunction(tokenHash, "symbol", []smartcontract.Parameter{}, nil)
 	if err != nil {
 		return "", err
 	} else if result.State != "HALT" || len(result.Stack) == 0 {
@@ -61,7 +60,7 @@ func (c *Client) NEP5Symbol(tokenHash util.Uint160) (string, error) {
 
 // NEP5TotalSupply invokes `totalSupply` NEP5 method on a specified contract.
 func (c *Client) NEP5TotalSupply(tokenHash util.Uint160) (int64, error) {
-	result, err := c.InvokeFunction(tokenHash.StringLE(), "totalSupply", []smartcontract.Parameter{}, nil)
+	result, err := c.InvokeFunction(tokenHash, "totalSupply", []smartcontract.Parameter{}, nil)
 	if err != nil {
 		return 0, err
 	} else if result.State != "HALT" || len(result.Stack) == 0 {
@@ -73,7 +72,7 @@ func (c *Client) NEP5TotalSupply(tokenHash util.Uint160) (int64, error) {
 
 // NEP5BalanceOf invokes `balanceOf` NEP5 method on a specified contract.
 func (c *Client) NEP5BalanceOf(tokenHash util.Uint160) (int64, error) {
-	result, err := c.InvokeFunction(tokenHash.StringLE(), "balanceOf", []smartcontract.Parameter{}, nil)
+	result, err := c.InvokeFunction(tokenHash, "balanceOf", []smartcontract.Parameter{}, nil)
 	if err != nil {
 		return 0, err
 	} else if result.State != "HALT" || len(result.Stack) == 0 {
@@ -127,7 +126,7 @@ func (c *Client) CreateNEP5TransferTx(acc *wallet.Account, to util.Uint160, toke
 		},
 	}
 
-	result, err := c.InvokeScript(hex.EncodeToString(script), []transaction.Cosigner{
+	result, err := c.InvokeScript(script, []transaction.Cosigner{
 		{
 			Account: from,
 			Scopes:  transaction.Global,
diff --git a/pkg/rpc/client/policy.go b/pkg/rpc/client/policy.go
index c366ce5f9..e0d9b46e6 100644
--- a/pkg/rpc/client/policy.go
+++ b/pkg/rpc/client/policy.go
@@ -29,7 +29,7 @@ func (c *Client) GetFeePerByte() (int64, error) {
 }
 
 func (c *Client) invokeNativePolicyMethod(operation string) (int64, error) {
-	result, err := c.InvokeFunction(PolicyContractHash.StringLE(), operation, []smartcontract.Parameter{}, nil)
+	result, err := c.InvokeFunction(PolicyContractHash, operation, []smartcontract.Parameter{}, nil)
 	if err != nil {
 		return 0, err
 	} else if result.State != "HALT" || len(result.Stack) == 0 {
@@ -41,7 +41,7 @@ func (c *Client) invokeNativePolicyMethod(operation string) (int64, error) {
 
 // GetBlockedAccounts invokes `getBlockedAccounts` method on a native Policy contract.
 func (c *Client) GetBlockedAccounts() (native.BlockedAccounts, error) {
-	result, err := c.InvokeFunction(PolicyContractHash.StringLE(), "getBlockedAccounts", []smartcontract.Parameter{}, nil)
+	result, err := c.InvokeFunction(PolicyContractHash, "getBlockedAccounts", []smartcontract.Parameter{}, nil)
 	if err != nil {
 		return nil, err
 	} else if result.State != "HALT" || len(result.Stack) == 0 {
diff --git a/pkg/rpc/client/rpc.go b/pkg/rpc/client/rpc.go
index dd342e6e5..7aac5ff41 100644
--- a/pkg/rpc/client/rpc.go
+++ b/pkg/rpc/client/rpc.go
@@ -349,36 +349,38 @@ func (c *Client) GetVersion() (*result.Version, error) {
 
 // InvokeScript returns the result of the given script after running it true the VM.
 // NOTE: This is a test invoke and will not affect the blockchain.
-func (c *Client) InvokeScript(script string, cosigners []transaction.Cosigner) (*result.Invoke, error) {
-	var (
-		params request.RawParams
-		resp   = &result.Invoke{}
-	)
-	if cosigners != nil {
-		params = request.NewRawParams(script, cosigners)
-	} else {
-		params = request.NewRawParams(script)
-	}
-	if err := c.performRequest("invokescript", params, resp); err != nil {
-		return nil, err
-	}
-	return resp, nil
+func (c *Client) InvokeScript(script []byte, cosigners []transaction.Cosigner) (*result.Invoke, error) {
+	var p = request.NewRawParams(hex.EncodeToString(script))
+	return c.invokeSomething("invokescript", p, cosigners)
 }
 
 // InvokeFunction returns the results after calling the smart contract scripthash
 // with the given operation and parameters.
 // NOTE: this is test invoke and will not affect the blockchain.
-func (c *Client) InvokeFunction(script, operation string, params []smartcontract.Parameter, cosigners []transaction.Cosigner) (*result.Invoke, error) {
-	var (
-		p    request.RawParams
-		resp = &result.Invoke{}
-	)
+func (c *Client) InvokeFunction(contract util.Uint160, operation string, params []smartcontract.Parameter, cosigners []transaction.Cosigner) (*result.Invoke, error) {
+	var p = request.NewRawParams(contract.StringLE(), operation, params)
+	return c.invokeSomething("invokefunction", p, cosigners)
+}
+
+// invokeSomething is an inner wrapper for Invoke* functions
+func (c *Client) invokeSomething(method string, p request.RawParams, cosigners []transaction.Cosigner) (*result.Invoke, error) {
+	var resp = new(result.Invoke)
 	if cosigners != nil {
-		p = request.NewRawParams(script, operation, params, cosigners)
-	} else {
-		p = request.NewRawParams(script, operation, params)
+		p.Values = append(p.Values, cosigners)
 	}
-	if err := c.performRequest("invokefunction", p, resp); err != nil {
+	if err := c.performRequest(method, p, resp); err != nil {
+		// Retry with old-fashioned hashes (see neo/neo-modules#260).
+		if cosigners != nil {
+			var hashes = make([]util.Uint160, len(cosigners))
+			for i := range cosigners {
+				hashes[i] = cosigners[i].Account
+			}
+			p.Values[len(p.Values)-1] = hashes
+			err = c.performRequest(method, p, resp)
+			if err == nil {
+				return resp, nil
+			}
+		}
 		return nil, err
 	}
 	return resp, nil
diff --git a/pkg/rpc/client/rpc_test.go b/pkg/rpc/client/rpc_test.go
index d2d9c0693..93741e7b0 100644
--- a/pkg/rpc/client/rpc_test.go
+++ b/pkg/rpc/client/rpc_test.go
@@ -616,7 +616,11 @@ var rpcClientTestCases = map[string][]rpcClientTestCase{
 				if err != nil {
 					panic(err)
 				}
-				return c.InvokeFunction("af7c7328eee5a275a3bcaee2bf0cf662b5e739be", "balanceOf", []smartcontract.Parameter{
+				contr, err := util.Uint160DecodeStringLE("af7c7328eee5a275a3bcaee2bf0cf662b5e739be")
+				if err != nil {
+					panic(err)
+				}
+				return c.InvokeFunction(contr, "balanceOf", []smartcontract.Parameter{
 					{
 						Type:  smartcontract.Hash160Type,
 						Value: hash,
@@ -649,7 +653,11 @@ var rpcClientTestCases = map[string][]rpcClientTestCase{
 		{
 			name: "positive",
 			invoke: func(c *Client) (interface{}, error) {
-				return c.InvokeScript("00046e616d656724058e5e1b6008847cd662728549088a9ee82191", []transaction.Cosigner{{
+				script, err := hex.DecodeString("00046e616d656724058e5e1b6008847cd662728549088a9ee82191")
+				if err != nil {
+					panic(err)
+				}
+				return c.InvokeScript(script, []transaction.Cosigner{{
 					Account: util.Uint160{1, 2, 3},
 				}})
 			},
@@ -952,13 +960,13 @@ var rpcClientErrorCases = map[string][]rpcClientErrorCase{
 		{
 			name: "invokefunction_invalid_params_error",
 			invoke: func(c *Client) (interface{}, error) {
-				return c.InvokeFunction("", "", []smartcontract.Parameter{}, nil)
+				return c.InvokeFunction(util.Uint160{}, "", []smartcontract.Parameter{}, nil)
 			},
 		},
 		{
 			name: "invokescript_invalid_params_error",
 			invoke: func(c *Client) (interface{}, error) {
-				return c.InvokeScript("", nil)
+				return c.InvokeScript([]byte{}, nil)
 			},
 		},
 		{
@@ -1134,13 +1142,13 @@ var rpcClientErrorCases = map[string][]rpcClientErrorCase{
 		{
 			name: "invokefunction_unmarshalling_error",
 			invoke: func(c *Client) (interface{}, error) {
-				return c.InvokeFunction("", "", []smartcontract.Parameter{}, nil)
+				return c.InvokeFunction(util.Uint160{}, "", []smartcontract.Parameter{}, nil)
 			},
 		},
 		{
 			name: "invokescript_unmarshalling_error",
 			invoke: func(c *Client) (interface{}, error) {
-				return c.InvokeScript("", nil)
+				return c.InvokeScript([]byte{}, nil)
 			},
 		},
 		{
diff --git a/pkg/rpc/request/txBuilder.go b/pkg/rpc/request/txBuilder.go
index 953ef7287..f8db67de2 100644
--- a/pkg/rpc/request/txBuilder.go
+++ b/pkg/rpc/request/txBuilder.go
@@ -5,7 +5,6 @@ import (
 	"fmt"
 	"strconv"
 
-	"github.com/nspcc-dev/neo-go/pkg/core"
 	"github.com/nspcc-dev/neo-go/pkg/crypto/keys"
 	"github.com/nspcc-dev/neo-go/pkg/io"
 	"github.com/nspcc-dev/neo-go/pkg/smartcontract"
@@ -16,18 +15,17 @@ import (
 )
 
 // CreateDeploymentScript returns a script that deploys given smart contract
-// with its metadata and system fee require for this.
-func CreateDeploymentScript(avm []byte, manif *manifest.Manifest) ([]byte, int64, error) {
+// with its metadata.
+func CreateDeploymentScript(avm []byte, manif *manifest.Manifest) ([]byte, error) {
 	script := io.NewBufBinWriter()
 	rawManifest, err := manif.MarshalJSON()
 	if err != nil {
-		return nil, 0, err
+		return nil, err
 	}
 	emit.Bytes(script.BinWriter, rawManifest)
 	emit.Bytes(script.BinWriter, avm)
 	emit.Syscall(script.BinWriter, "System.Contract.Create")
-	sysfee := int64(core.StoragePrice * (len(avm) + len(rawManifest)))
-	return script.Bytes(), sysfee, nil
+	return script.Bytes(), nil
 }
 
 // expandArrayIntoScript pushes all FuncParam parameters from the given array