diff --git a/consensus/ethash/algorithm_test.go b/consensus/ethash/algorithm_test.go
index ca17ae019c..38477f0f71 100644
--- a/consensus/ethash/algorithm_test.go
+++ b/consensus/ethash/algorithm_test.go
@@ -703,7 +703,7 @@ func TestConcurrentDiskCacheGeneration(t *testing.T) {
 
 		go func(idx int) {
 			defer pend.Done()
-			ethash := New(Config{cachedir, 0, 1, "", 0, 0, false, false, false, false})
+			ethash := New(Config{cachedir, 0, 1, "", 0, 0, Normal})
 			if err := ethash.VerifySeal(nil, block.Header()); err != nil {
 				t.Errorf("proc %d: block verification failed: %v", idx, err)
 			}
diff --git a/consensus/ethash/consensus.go b/consensus/ethash/consensus.go
index 684f470764..7a598e8e81 100644
--- a/consensus/ethash/consensus.go
+++ b/consensus/ethash/consensus.go
@@ -68,7 +68,7 @@ func (ethash *Ethash) Author(header *types.Header) (common.Address, error) {
 // stock Ethereum ethash engine.
 func (ethash *Ethash) VerifyHeader(chain consensus.ChainReader, header *types.Header, seal bool) error {
 	// If we're running a full engine faking, accept any input as valid
-	if ethash.config.FullFake {
+	if ethash.config.PowMode == FullFake {
 		return nil
 	}
 	// Short circuit if the header is known, or it's parent not
@@ -89,7 +89,7 @@ func (ethash *Ethash) VerifyHeader(chain consensus.ChainReader, header *types.He
 // a results channel to retrieve the async verifications.
 func (ethash *Ethash) VerifyHeaders(chain consensus.ChainReader, headers []*types.Header, seals []bool) (chan<- struct{}, <-chan error) {
 	// If we're running a full engine faking, accept any input as valid
-	if ethash.config.FullFake || len(headers) == 0 {
+	if ethash.config.PowMode == FullFake || len(headers) == 0 {
 		abort, results := make(chan struct{}), make(chan error, len(headers))
 		for i := 0; i < len(headers); i++ {
 			results <- nil
@@ -169,7 +169,7 @@ func (ethash *Ethash) verifyHeaderWorker(chain consensus.ChainReader, headers []
 // rules of the stock Ethereum ethash engine.
 func (ethash *Ethash) VerifyUncles(chain consensus.ChainReader, block *types.Block) error {
 	// If we're running a full engine faking, accept any input as valid
-	if ethash.config.FullFake {
+	if ethash.config.PowMode == FullFake {
 		return nil
 	}
 	// Verify that there are at most 2 uncles included in this block
@@ -455,7 +455,7 @@ func calcDifficultyFrontier(time uint64, parent *types.Header) *big.Int {
 // the PoW difficulty requirements.
 func (ethash *Ethash) VerifySeal(chain consensus.ChainReader, header *types.Header) error {
 	// If we're running a fake PoW, accept any seal as valid
-	if ethash.config.Fake {
+	if ethash.config.PowMode == Fake || ethash.config.PowMode == FullFake {
 		time.Sleep(ethash.fakeDelay)
 		if ethash.fakeFail == header.Number.Uint64() {
 			return errInvalidPoW
@@ -480,7 +480,7 @@ func (ethash *Ethash) VerifySeal(chain consensus.ChainReader, header *types.Head
 	cache := ethash.cache(number)
 
 	size := datasetSize(number)
-	if ethash.config.Test {
+	if ethash.config.PowMode == Test {
 		size = 32 * 1024
 	}
 	digest, result := hashimotoLight(size, cache, header.HashNoNonce().Bytes(), header.Nonce.Uint64())
diff --git a/consensus/ethash/ethash.go b/consensus/ethash/ethash.go
index b3d4b2b4b6..78efae1d48 100644
--- a/consensus/ethash/ethash.go
+++ b/consensus/ethash/ethash.go
@@ -45,7 +45,7 @@ var (
 	maxUint256 = new(big.Int).Exp(big.NewInt(2), big.NewInt(256), big.NewInt(0))
 
 	// sharedEthash is a full instance that can be shared between multiple users.
-	sharedEthash = New(Config{"", 3, 0, "", 1, 0, false, false, false, false})
+	sharedEthash = New(Config{"", 3, 0, "", 1, 0, Normal})
 
 	// algorithmRevision is the data structure version used for file naming.
 	algorithmRevision = 23
@@ -320,6 +320,16 @@ func MakeDataset(block uint64, dir string) {
 	d.release()
 }
 
+type Mode uint
+
+const (
+	Normal Mode = iota
+	Shared
+	Test
+	Fake
+	FullFake
+)
+
 // Config are the configuration parameters of the ethash.
 type Config struct {
 	CacheDir       string
@@ -328,12 +338,7 @@ type Config struct {
 	DatasetDir     string
 	DatasetsInMem  int
 	DatasetsOnDisk int
-
-	// The fields below are configurations for testing
-	Fake     bool
-	FullFake bool
-	Test     bool
-	Shared   bool
+	PowMode        Mode
 }
 
 // Ethash is a consensus engine based on proot-of-work implementing the ethash
@@ -387,7 +392,7 @@ func NewTester() *Ethash {
 	return &Ethash{
 		config: Config{
 			CachesInMem: 1,
-			Test:        true,
+			PowMode:     Test,
 		},
 		caches:   make(map[uint64]*cache),
 		datasets: make(map[uint64]*dataset),
@@ -402,7 +407,7 @@ func NewTester() *Ethash {
 func NewFaker() *Ethash {
 	return &Ethash{
 		config: Config{
-			Fake: true,
+			PowMode: Fake,
 		},
 	}
 }
@@ -413,7 +418,7 @@ func NewFaker() *Ethash {
 func NewFakeFailer(fail uint64) *Ethash {
 	return &Ethash{
 		config: Config{
-			Fake: true,
+			PowMode: Fake,
 		},
 		fakeFail: fail,
 	}
@@ -425,7 +430,7 @@ func NewFakeFailer(fail uint64) *Ethash {
 func NewFakeDelayer(delay time.Duration) *Ethash {
 	return &Ethash{
 		config: Config{
-			Fake: true,
+			PowMode: Fake,
 		},
 		fakeDelay: delay,
 	}
@@ -436,8 +441,7 @@ func NewFakeDelayer(delay time.Duration) *Ethash {
 func NewFullFaker() *Ethash {
 	return &Ethash{
 		config: Config{
-			Fake:     true,
-			FullFake: true,
+			PowMode: FullFake,
 		},
 	}
 }
@@ -497,7 +501,7 @@ func (ethash *Ethash) cache(block uint64) []uint32 {
 	ethash.lock.Unlock()
 
 	// Wait for generation finish, bump the timestamp and finalize the cache
-	current.generate(ethash.config.CacheDir, ethash.config.CachesOnDisk, ethash.config.Test)
+	current.generate(ethash.config.CacheDir, ethash.config.CachesOnDisk, ethash.config.PowMode == Test)
 
 	current.lock.Lock()
 	current.used = time.Now()
@@ -505,7 +509,7 @@ func (ethash *Ethash) cache(block uint64) []uint32 {
 
 	// If we exhausted the future cache, now's a good time to regenerate it
 	if future != nil {
-		go future.generate(ethash.config.CacheDir, ethash.config.CachesOnDisk, ethash.config.Test)
+		go future.generate(ethash.config.CacheDir, ethash.config.CachesOnDisk, ethash.config.PowMode == Test)
 	}
 	return current.cache
 }
@@ -560,7 +564,7 @@ func (ethash *Ethash) dataset(block uint64) []uint32 {
 	ethash.lock.Unlock()
 
 	// Wait for generation finish, bump the timestamp and finalize the cache
-	current.generate(ethash.config.DatasetDir, ethash.config.DatasetsOnDisk, ethash.config.Test)
+	current.generate(ethash.config.DatasetDir, ethash.config.DatasetsOnDisk, ethash.config.PowMode == Test)
 
 	current.lock.Lock()
 	current.used = time.Now()
@@ -568,7 +572,7 @@ func (ethash *Ethash) dataset(block uint64) []uint32 {
 
 	// If we exhausted the future dataset, now's a good time to regenerate it
 	if future != nil {
-		go future.generate(ethash.config.DatasetDir, ethash.config.DatasetsOnDisk, ethash.config.Test)
+		go future.generate(ethash.config.DatasetDir, ethash.config.DatasetsOnDisk, ethash.config.PowMode == Test)
 	}
 	return current.dataset
 }
diff --git a/consensus/ethash/sealer.go b/consensus/ethash/sealer.go
index 62d056dd09..d7cceb11d4 100644
--- a/consensus/ethash/sealer.go
+++ b/consensus/ethash/sealer.go
@@ -34,7 +34,7 @@ import (
 // the block's difficulty requirements.
 func (ethash *Ethash) Seal(chain consensus.ChainReader, block *types.Block, stop <-chan struct{}) (*types.Block, error) {
 	// If we're running a fake PoW, simply return a 0 nonce immediately
-	if ethash.config.Fake {
+	if ethash.config.PowMode == Fake || ethash.config.PowMode == FullFake {
 		header := block.Header()
 		header.Nonce, header.MixDigest = types.BlockNonce{}, common.Hash{}
 		return block.WithSeal(header), nil
diff --git a/console/console_test.go b/console/console_test.go
index 492a55733f..98d0feddac 100644
--- a/console/console_test.go
+++ b/console/console_test.go
@@ -98,7 +98,7 @@ func newTester(t *testing.T, confOverride func(*eth.Config)) *tester {
 		Genesis:   core.DeveloperGenesisBlock(15, common.Address{}),
 		Etherbase: common.HexToAddress(testAddress),
 		Ethash: ethash.Config{
-			Test: true,
+			PowMode: ethash.Test,
 		},
 	}
 	if confOverride != nil {
diff --git a/eth/backend.go b/eth/backend.go
index 1104e8909e..8d08feca60 100644
--- a/eth/backend.go
+++ b/eth/backend.go
@@ -216,13 +216,13 @@ func CreateConsensusEngine(ctx *node.ServiceContext, config *ethash.Config, chai
 	}
 	// Otherwise assume proof-of-work
 	switch {
-	case config.Fake:
+	case config.PowMode == ethash.Fake:
 		log.Warn("Ethash used in fake mode")
 		return ethash.NewFaker()
-	case config.Test:
+	case config.PowMode == ethash.Test:
 		log.Warn("Ethash used in test mode")
 		return ethash.NewTester()
-	case config.Shared:
+	case config.PowMode == ethash.Shared:
 		log.Warn("Ethash used in shared mode")
 		return ethash.NewShared()
 	default:
diff --git a/eth/gen_config.go b/eth/gen_config.go
index 134fae7465..e2d50e1f66 100644
--- a/eth/gen_config.go
+++ b/eth/gen_config.go
@@ -7,6 +7,7 @@ import (
 
 	"github.com/ethereum/go-ethereum/common"
 	"github.com/ethereum/go-ethereum/common/hexutil"
+	"github.com/ethereum/go-ethereum/consensus/ethash"
 	"github.com/ethereum/go-ethereum/core"
 	"github.com/ethereum/go-ethereum/eth/downloader"
 	"github.com/ethereum/go-ethereum/eth/gasprice"
@@ -36,10 +37,8 @@ func (c Config) MarshalTOML() (interface{}, error) {
 		TxPool                  core.TxPoolConfig
 		GPO                     gasprice.Config
 		EnablePreimageRecording bool
-		DocRoot                 string `toml:"-"`
-		PowFake                 bool   `toml:"-"`
-		PowTest                 bool   `toml:"-"`
-		PowShared               bool   `toml:"-"`
+		DocRoot                 string      `toml:"-"`
+		PowMode                 ethash.Mode `toml:"-"`
 	}
 	var enc Config
 	enc.Genesis = c.Genesis
@@ -64,9 +63,7 @@ func (c Config) MarshalTOML() (interface{}, error) {
 	enc.GPO = c.GPO
 	enc.EnablePreimageRecording = c.EnablePreimageRecording
 	enc.DocRoot = c.DocRoot
-	enc.PowFake = c.Ethash.Fake
-	enc.PowTest = c.Ethash.Test
-	enc.PowShared = c.Ethash.Shared
+	enc.PowMode = c.Ethash.PowMode
 	return &enc, nil
 }
 
@@ -94,10 +91,8 @@ func (c *Config) UnmarshalTOML(unmarshal func(interface{}) error) error {
 		TxPool                  *core.TxPoolConfig
 		GPO                     *gasprice.Config
 		EnablePreimageRecording *bool
-		DocRoot                 *string `toml:"-"`
-		PowFake                 *bool   `toml:"-"`
-		PowTest                 *bool   `toml:"-"`
-		PowShared               *bool   `toml:"-"`
+		DocRoot                 *string      `toml:"-"`
+		PowMode                 *ethash.Mode `toml:"-"`
 	}
 	var dec Config
 	if err := unmarshal(&dec); err != nil {
@@ -169,14 +164,8 @@ func (c *Config) UnmarshalTOML(unmarshal func(interface{}) error) error {
 	if dec.DocRoot != nil {
 		c.DocRoot = *dec.DocRoot
 	}
-	if dec.PowFake != nil {
-		c.Ethash.Fake = *dec.PowFake
-	}
-	if dec.PowTest != nil {
-		c.Ethash.Test = *dec.PowTest
-	}
-	if dec.PowShared != nil {
-		c.Ethash.Shared = *dec.PowShared
+	if dec.PowMode != nil {
+		c.Ethash.PowMode = *dec.PowMode
 	}
 	return nil
 }