diff --git a/adb/adb.cpp b/adb/adb.cpp
index 89a20f0..29d6e65 100644
--- a/adb/adb.cpp
+++ b/adb/adb.cpp
@@ -94,6 +94,18 @@
     abort();
 }
 
+uint32_t calculate_apacket_checksum(const apacket* p) {
+    const unsigned char* x = reinterpret_cast<const unsigned char*>(p->data);
+    uint32_t sum = 0;
+    size_t count = p->msg.data_length;
+
+    while (count-- > 0) {
+        sum += *x++;
+    }
+
+    return sum;
+}
+
 apacket* get_apacket(void)
 {
     apacket* p = reinterpret_cast<apacket*>(malloc(sizeof(apacket)));
diff --git a/adb/adb.h b/adb/adb.h
index 0b9fe5b..8064c17 100644
--- a/adb/adb.h
+++ b/adb/adb.h
@@ -18,6 +18,7 @@
 #define __ADB_H
 
 #include <limits.h>
+#include <stdint.h>
 #include <sys/types.h>
 
 #include <string>
@@ -56,25 +57,27 @@
 struct usb_handle;
 
 struct amessage {
-    unsigned command;       /* command identifier constant      */
-    unsigned arg0;          /* first argument                   */
-    unsigned arg1;          /* second argument                  */
-    unsigned data_length;   /* length of payload (0 is allowed) */
-    unsigned data_check;    /* checksum of data payload         */
-    unsigned magic;         /* command ^ 0xffffffff             */
+    uint32_t command;     /* command identifier constant      */
+    uint32_t arg0;        /* first argument                   */
+    uint32_t arg1;        /* second argument                  */
+    uint32_t data_length; /* length of payload (0 is allowed) */
+    uint32_t data_check;  /* checksum of data payload         */
+    uint32_t magic;       /* command ^ 0xffffffff             */
 };
 
 struct apacket
 {
     apacket *next;
 
-    unsigned len;
-    unsigned char *ptr;
+    size_t len;
+    char* ptr;
 
     amessage msg;
-    unsigned char data[MAX_PAYLOAD];
+    char data[MAX_PAYLOAD];
 };
 
+uint32_t calculate_apacket_checksum(const apacket* packet);
+
 /* the adisconnect structure is used to record a callback that
 ** will be called whenever a transport is disconnected (e.g. by the user)
 ** this should be used to cleanup objects that depend on the
diff --git a/adb/adb_auth.h b/adb/adb_auth.h
index 4db83a4..a6f224f 100644
--- a/adb/adb_auth.h
+++ b/adb/adb_auth.h
@@ -36,11 +36,10 @@
 void adb_auth_init();
 
 int adb_auth_keygen(const char* filename);
-int adb_auth_sign(RSA* key, const unsigned char* token, size_t token_size, unsigned char* sig);
 std::string adb_auth_get_userkey();
 std::deque<std::shared_ptr<RSA>> adb_auth_get_private_keys();
 
-void send_auth_response(uint8_t *token, size_t token_size, atransport *t);
+void send_auth_response(const char* token, size_t token_size, atransport* t);
 
 #else // !ADB_HOST
 
@@ -50,8 +49,8 @@
 void adbd_auth_verified(atransport *t);
 
 void adbd_cloexec_auth_socket();
-bool adbd_auth_verify(uint8_t* token, size_t token_size, uint8_t* sig, int sig_len);
-void adbd_auth_confirm_key(unsigned char *data, size_t len, atransport *t);
+bool adbd_auth_verify(const char* token, size_t token_size, const char* sig, int sig_len);
+void adbd_auth_confirm_key(const char* data, size_t len, atransport* t);
 
 void send_auth_request(atransport *t);
 
diff --git a/adb/adb_auth_host.cpp b/adb/adb_auth_host.cpp
index b5b9b97..ff2d76d 100644
--- a/adb/adb_auth_host.cpp
+++ b/adb/adb_auth_host.cpp
@@ -298,14 +298,15 @@
     return result;
 }
 
-int adb_auth_sign(RSA* key, const unsigned char* token, size_t token_size, unsigned char* sig) {
+static int adb_auth_sign(RSA* key, const char* token, size_t token_size, char* sig) {
     if (token_size != TOKEN_SIZE) {
         D("Unexpected token size %zd", token_size);
         return 0;
     }
 
     unsigned int len;
-    if (!RSA_sign(NID_sha1, token, token_size, sig, &len, key)) {
+    if (!RSA_sign(NID_sha1, reinterpret_cast<const uint8_t*>(token), token_size,
+                  reinterpret_cast<uint8_t*>(sig), &len, key)) {
         return 0;
     }
 
@@ -448,7 +449,7 @@
     send_packet(p, t);
 }
 
-void send_auth_response(uint8_t* token, size_t token_size, atransport* t) {
+void send_auth_response(const char* token, size_t token_size, atransport* t) {
     std::shared_ptr<RSA> key = t->NextKey();
     if (key == nullptr) {
         // No more private keys to try, send the public key.
diff --git a/adb/adbd_auth.cpp b/adb/adbd_auth.cpp
index fa76c8d..b5f87be 100644
--- a/adb/adbd_auth.cpp
+++ b/adb/adbd_auth.cpp
@@ -46,7 +46,7 @@
 
 bool auth_required = true;
 
-bool adbd_auth_verify(uint8_t* token, size_t token_size, uint8_t* sig, int sig_len) {
+bool adbd_auth_verify(const char* token, size_t token_size, const char* sig, int sig_len) {
     static constexpr const char* key_paths[] = { "/adb_keys", "/data/misc/adb/adb_keys", nullptr };
 
     for (const auto& path : key_paths) {
@@ -78,7 +78,9 @@
                     continue;
                 }
 
-                bool verified = (RSA_verify(NID_sha1, token, token_size, sig, sig_len, key) == 1);
+                bool verified =
+                    (RSA_verify(NID_sha1, reinterpret_cast<const uint8_t*>(token), token_size,
+                                reinterpret_cast<const uint8_t*>(sig), sig_len, key) == 1);
                 RSA_free(key);
                 if (verified) return true;
             }
@@ -121,7 +123,7 @@
     }
 }
 
-void adbd_auth_confirm_key(unsigned char* key, size_t len, atransport* t) {
+void adbd_auth_confirm_key(const char* key, size_t len, atransport* t) {
     if (!usb_transport) {
         usb_transport = t;
         t->AddDisconnect(&usb_disconnect);
diff --git a/adb/sockets.cpp b/adb/sockets.cpp
index b809c4f..fff6049 100644
--- a/adb/sockets.cpp
+++ b/adb/sockets.cpp
@@ -122,7 +122,7 @@
 }
 
 static int local_socket_enqueue(asocket* s, apacket* p) {
-    D("LS(%d): enqueue %d", s->id, p->len);
+    D("LS(%d): enqueue %zu", s->id, p->len);
 
     p->ptr = p->data;
 
@@ -195,7 +195,7 @@
 
     /* dispose of any unwritten data */
     for (p = s->pkt_first; p; p = n) {
-        D("LS(%d): discarding %d bytes", s->id, p->len);
+        D("LS(%d): discarding %zu bytes", s->id, p->len);
         n = p->next;
         put_apacket(p);
     }
@@ -305,7 +305,7 @@
 
     if (ev & FDE_READ) {
         apacket* p = get_apacket();
-        unsigned char* x = p->data;
+        char* x = p->data;
         const size_t max_payload = s->get_max_payload();
         size_t avail = max_payload;
         int r = 0;
@@ -553,7 +553,7 @@
     s->close(s);
 }
 
-static unsigned unhex(unsigned char* s, int len) {
+static unsigned unhex(char* s, int len) {
     unsigned n = 0, c;
 
     while (len-- > 0) {
@@ -665,7 +665,7 @@
     TransportType type = kTransportAny;
 #endif
 
-    D("SS(%d): enqueue %d", s->id, p->len);
+    D("SS(%d): enqueue %zu", s->id, p->len);
 
     if (s->pkt_first == 0) {
         s->pkt_first = p;
@@ -698,7 +698,7 @@
     D("SS(%d): len is %d", s->id, len);
     /* can't do anything until we have the full header */
     if ((len + 4) > p->len) {
-        D("SS(%d): waiting for %d more bytes", s->id, len + 4 - p->len);
+        D("SS(%d): waiting for %zu more bytes", s->id, len + 4 - p->len);
         return 0;
     }
 
diff --git a/adb/transport.cpp b/adb/transport.cpp
index 9880902..7b4bb1c 100644
--- a/adb/transport.cpp
+++ b/adb/transport.cpp
@@ -150,32 +150,17 @@
     }
 }
 
-void send_packet(apacket *p, atransport *t)
-{
-    unsigned char *x;
-    unsigned sum;
-    unsigned count;
-
+void send_packet(apacket* p, atransport* t) {
     p->msg.magic = p->msg.command ^ 0xffffffff;
-
-    count = p->msg.data_length;
-    x = (unsigned char *) p->data;
-    sum = 0;
-    while(count-- > 0){
-        sum += *x++;
-    }
-    p->msg.data_check = sum;
+    p->msg.data_check = calculate_apacket_checksum(p);
 
     print_packet("send", p);
 
     if (t == NULL) {
-        D("Transport is null");
-        // Zap errno because print_packet() and other stuff have errno effect.
-        errno = 0;
-        fatal_errno("Transport is null");
+        fatal("Transport is null");
     }
 
-    if(write_packet(t->transport_socket, t->serial, &p)){
+    if (write_packet(t->transport_socket, t->serial, &p)) {
         fatal_errno("cannot enqueue packet on transport socket");
     }
 }
@@ -1052,23 +1037,11 @@
     return 0;
 }
 
-int check_data(apacket *p)
-{
-    unsigned count, sum;
-    unsigned char *x;
-
-    count = p->msg.data_length;
-    x = p->data;
-    sum = 0;
-    while(count-- > 0) {
-        sum += *x++;
-    }
-
-    if(sum != p->msg.data_check) {
+int check_data(apacket* p) {
+    if (calculate_apacket_checksum(p) != p->msg.data_check) {
         return -1;
-    } else {
-        return 0;
     }
+    return 0;
 }
 
 #if ADB_HOST
diff --git a/adb/transport.h b/adb/transport.h
index aaa8be4..621516c 100644
--- a/adb/transport.h
+++ b/adb/transport.h
@@ -112,7 +112,7 @@
     std::shared_ptr<RSA> NextKey();
 #endif
 
-    unsigned char token[TOKEN_SIZE] = {};
+    char token[TOKEN_SIZE] = {};
     size_t failed_auth_attempts = 0;
 
     const std::string connection_state_name() const;