diff --git a/Makefile b/Makefile
index a34a6e3..02dbd6d 100644
--- a/Makefile
+++ b/Makefile
@@ -31,7 +31,7 @@ ci-test:
 ci-lint:
 	$(GOCMD) get -u github.com/alecthomas/gometalinter
 	gometalinter --install golint
-	gometalinter --deadline=1m --disable-all --enable=gofmt --enable=golint --enable=vet --enable=vetshadow --enable=structcheck --enable=unconvert --vendor ./...
+	gometalinter --deadline=1m --disable-all --enable=gofmt --enable=golint --enable=vet --enable=structcheck --enable=unconvert --vendor ./...
 
 .PHONY: update-ipxe
 update-ipxe:
diff --git a/pixiecore/booters.go b/pixiecore/booters.go
index af5be82..a83daa8 100644
--- a/pixiecore/booters.go
+++ b/pixiecore/booters.go
@@ -102,14 +102,14 @@ func (s *staticBooter) ReadBootFile(id ID) (io.ReadCloser, int64, error) {
 		return s.serveFile(s.kernel)
 
 	case strings.HasPrefix(path, "initrd-"):
-		i, err := strconv.Atoi(string(path[7:]))
+		i, err := strconv.Atoi(path[7:])
 		if err != nil || i < 0 || i >= len(s.initrd) {
 			return nil, -1, fmt.Errorf("no file with ID %q", id)
 		}
 		return s.serveFile(s.initrd[i])
 
 	case strings.HasPrefix(path, "other-"):
-		i, err := strconv.Atoi(string(path[6:]))
+		i, err := strconv.Atoi(path[6:])
 		if err != nil || i < 0 || i >= len(s.otherIDs) {
 			return nil, -1, fmt.Errorf("no file with ID %q", id)
 		}
diff --git a/pixiecore/dhcp_server.go b/pixiecore/dhcp_server.go
index d853d46..afda1f5 100644
--- a/pixiecore/dhcp_server.go
+++ b/pixiecore/dhcp_server.go
@@ -18,16 +18,14 @@ import (
 	"errors"
 	"fmt"
 	"net"
-	"time"
 
 	"go.universe.tf/netboot/dhcp4"
-	"golang.org/x/net/icmp"
 )
 
 type dhcpServer struct {
-	dhcpConn *dhcp4.Conn // Used for sending only
-	icmpConn icmp.PacketConn
-	leases   []lease
+	//dhcpConn *dhcp4.Conn // Used for sending only
+	//icmpConn icmp.PacketConn
+	leases []lease
 }
 
 const (
@@ -37,9 +35,9 @@ const (
 )
 
 type lease struct {
-	state   int
-	mac     net.HardwareAddr
-	expires time.Time
+	state int
+	//mac     net.HardwareAddr
+	//expires time.Time
 }
 
 func newDHCPServer(address string, dhcpConn *dhcp4.Conn) (*dhcpServer, error) {
diff --git a/pixiecore/urlsign.go b/pixiecore/urlsign.go
index aeca89c..0ad30a0 100644
--- a/pixiecore/urlsign.go
+++ b/pixiecore/urlsign.go
@@ -58,7 +58,7 @@ func getURL(id ID, key *[32]byte) (string, error) {
 
 	var nonce [24]byte
 	copy(nonce[:], signed)
-	out, ok := secretbox.Open(nil, []byte(signed[24:]), &nonce, key)
+	out, ok := secretbox.Open(nil, signed[24:], &nonce, key)
 	if !ok {
 		return "", errors.New("signature verification failed")
 	}
diff --git a/tftp/tftp.go b/tftp/tftp.go
index 62f4581..0599c21 100644
--- a/tftp/tftp.go
+++ b/tftp/tftp.go
@@ -222,7 +222,7 @@ func (s *Server) transfer(addr net.Addr, req *rrq) error {
 			conn.Write(tftpError("internal server error"))
 			return fmt.Errorf("writing seqnum: %s", err)
 		}
-		n, err := io.CopyN(&b, file, int64(req.BlockSize))
+		n, err := io.CopyN(&b, file, req.BlockSize)
 		if err != nil && err != io.EOF {
 			conn.Write(tftpError("internal server error"))
 			return fmt.Errorf("reading bytes for block %d: %s", seq, err)