diff --git a/build/params_debug.go b/build/params_debug.go
index 093566aa7..aaa58038b 100644
--- a/build/params_debug.go
+++ b/build/params_debug.go
@@ -29,6 +29,9 @@ const InteractivePoRepDelay = 2
 // Epochs
 const InteractivePoRepConfidence = 6
 
+// Bytes
+const MinimumMinerPower = 2 << 10 // 2KiB
+
 func init() {
 	os.Setenv("TRUST_PARAMS", "1")
 }
diff --git a/build/params_devnet.go b/build/params_devnet.go
index f187bf60a..ca356aff5 100644
--- a/build/params_devnet.go
+++ b/build/params_devnet.go
@@ -31,3 +31,6 @@ const InteractivePoRepDelay = 8
 
 // Epochs
 const InteractivePoRepConfidence = 6
+
+// Bytes
+const MinimumMinerPower = 20 << 30 // 20GB
diff --git a/build/params_shared.go b/build/params_shared.go
index 3d3bc9aac..755bda687 100644
--- a/build/params_shared.go
+++ b/build/params_shared.go
@@ -77,6 +77,7 @@ const CollateralPrecision = 1000
 const TotalFilecoin = 2_000_000_000
 const MiningRewardTotal = 1_400_000_000
 
+
 const InitialRewardStr = "153856861913558700202"
 
 var InitialReward *big.Int
diff --git a/chain/actors/actor_miner.go b/chain/actors/actor_miner.go
index 4e1ba5570..3360f5e25 100644
--- a/chain/actors/actor_miner.go
+++ b/chain/actors/actor_miner.go
@@ -926,8 +926,14 @@ func onSuccessfulPoSt(self *StorageMinerActorState, vmctx types.VMContext) aerro
 	self.FaultSet = types.NewBitField()
 
 	oldPower := self.Power
-	self.Power = types.BigMul(types.NewInt(pss.Count-uint64(len(faults))),
-		types.NewInt(mi.SectorSize))
+	newPower := types.BigMul(types.NewInt(pss.Count-uint64(len(faults))), types.NewInt(mi.SectorSize))
+
+	// If below the minimum size requirement, miners have zero power
+	if newPower.LessThan(types.NewInt(build.MinimumMinerPower)) {
+		newPower = types.NewInt(0)
+	}
+
+	self.Power = newPower
 
 	delta := types.BigSub(self.Power, oldPower)
 	if self.SlashedAt != 0 {
@@ -936,23 +942,25 @@ func onSuccessfulPoSt(self *StorageMinerActorState, vmctx types.VMContext) aerro
 	}
 
 	prevSlashingDeadline := self.ElectionPeriodStart + build.SlashablePowerDelay
-	if !self.Active {
+	if !self.Active && newPower.GreaterThan(types.NewInt(0)) {
 		self.Active = true
 		prevSlashingDeadline = 0
 	}
 
-	enc, err := SerializeParams(&UpdateStorageParams{
-		Delta:                    delta,
-		NextProvingPeriodEnd:     vmctx.BlockHeight() + build.SlashablePowerDelay,
-		PreviousProvingPeriodEnd: prevSlashingDeadline,
-	})
-	if err != nil {
-		return err
-	}
+	if !(oldPower.IsZero() && newPower.IsZero()) {
+		enc, err := SerializeParams(&UpdateStorageParams{
+			Delta:                    delta,
+			NextProvingPeriodEnd:     vmctx.BlockHeight() + build.SlashablePowerDelay,
+			PreviousProvingPeriodEnd: prevSlashingDeadline,
+		})
+		if err != nil {
+			return err
+		}
 
-	_, err = vmctx.Send(StoragePowerAddress, SPAMethods.UpdateStorage, types.NewInt(0), enc)
-	if err != nil {
-		return err
+		_, err = vmctx.Send(StoragePowerAddress, SPAMethods.UpdateStorage, types.NewInt(0), enc)
+		if err != nil {
+			return err
+		}
 	}
 
 	ncid, err := RemoveFromSectorSet(vmctx.Context(), vmctx.Storage(), self.Sectors, faults)
diff --git a/chain/types/bigint.go b/chain/types/bigint.go
index 266f2a8af..612fd34dc 100644
--- a/chain/types/bigint.go
+++ b/chain/types/bigint.go
@@ -237,3 +237,7 @@ func (bi *BigInt) UnmarshalCBOR(br io.Reader) error {
 
 	return nil
 }
+
+func (bi *BigInt) IsZero() bool {
+	return bi.Int.Sign() == 0
+}
diff --git a/lotuspond/spawn.go b/lotuspond/spawn.go
index f3534ece1..2146554b6 100644
--- a/lotuspond/spawn.go
+++ b/lotuspond/spawn.go
@@ -17,6 +17,10 @@ import (
 	"github.com/filecoin-project/lotus/cmd/lotus-seed/seed"
 )
 
+func init() {
+	build.SectorSizes = []uint64{1024}
+}
+
 func (api *api) Spawn() (nodeInfo, error) {
 	dir, err := ioutil.TempDir(os.TempDir(), "lotus-")
 	if err != nil {
@@ -36,7 +40,7 @@ func (api *api) Spawn() (nodeInfo, error) {
 		}
 
 		sbroot := filepath.Join(dir, "preseal")
-		genm, err := seed.PreSeal(genMiner, build.SectorSizes[0], 0, 1, sbroot, []byte("8"))
+		genm, err := seed.PreSeal(genMiner, build.SectorSizes[0], 0, 2, sbroot, []byte("8"))
 		if err != nil {
 			return nodeInfo{}, xerrors.Errorf("preseal failed: %w", err)
 		}
diff --git a/miner/miner.go b/miner/miner.go
index ee59f5d59..98def0e07 100644
--- a/miner/miner.go
+++ b/miner/miner.go
@@ -170,8 +170,6 @@ eventLoop:
 		}
 		lastBase = *base
 
-		log.Infof("Time delta between now and our mining base: %ds", uint64(time.Now().Unix())-base.ts.MinTimestamp())
-
 		blks := make([]*types.BlockMsg, 0)
 
 		for _, addr := range addrs {
@@ -272,6 +270,8 @@ func (m *Miner) mineOne(ctx context.Context, addr address.Address, base *MiningB
 		return nil, nil
 	}
 
+	log.Infof("Time delta between now and our mining base: %ds", uint64(time.Now().Unix())-base.ts.MinTimestamp())
+
 	ticket, err := m.computeTicket(ctx, addr, base)
 	if err != nil {
 		return nil, xerrors.Errorf("scratching ticket failed: %w", err)