diff --git a/Changelog.md b/Changelog.md
index ea31429..6000631 100644
--- a/Changelog.md
+++ b/Changelog.md
@@ -2,6 +2,14 @@
 
 ## [Unreleased]
 
+## [4.0.0] - 2024-05-06
+
+Breaking Changes
+
+- [appkey] Update signature of appkey functions to return bool instead of uint8_t
+- [appkey] Change return values of appkey to indicate SUCCESS status to be consistent with other functions
+- [hashing] All hashing/base64 functions have been updated similarly to return bool status of success instead of error
+
 ## [3.0.4] - 2024-05-05
 
 - [apple2] Add appkey support (thanks Eric Carr)
diff --git a/apple2/src/fn_fuji/fuji_appkey_open.c b/apple2/src/fn_fuji/fuji_appkey_open.c
index 33d66e3..eb162d3 100644
--- a/apple2/src/fn_fuji/fuji_appkey_open.c
+++ b/apple2/src/fn_fuji/fuji_appkey_open.c
@@ -2,7 +2,8 @@
 #include "fujinet-fuji.h"
 #include "fujinet-bus-apple2.h"
 
-uint8_t fuji_appkey_open(AppKeyOpen *buffer)
+// Open app-key, returns error status
+bool fuji_appkey_open(AppKeyOpen *buffer)
 {
 	sp_error = sp_get_fuji_id();
 	if (sp_error <= 0) {
diff --git a/apple2/src/fn_fuji/fuji_appkey_read.c b/apple2/src/fn_fuji/fuji_appkey_read.c
index 416cbf4..30e9b2e 100644
--- a/apple2/src/fn_fuji/fuji_appkey_read.c
+++ b/apple2/src/fn_fuji/fuji_appkey_read.c
@@ -3,7 +3,8 @@
 #include "fujinet-fuji.h"
 #include "fujinet-bus-apple2.h"
 
-uint8_t fuji_appkey_read(AppKeyRead *buffer)
+// reads the app-key, returns error status
+bool fuji_appkey_read(AppKeyRead *buffer)
 {
 	sp_error = sp_get_fuji_id();
 	if (sp_error <= 0) {
diff --git a/apple2/src/fn_fuji/fuji_appkey_write.c b/apple2/src/fn_fuji/fuji_appkey_write.c
index e3b309a..b54683d 100644
--- a/apple2/src/fn_fuji/fuji_appkey_write.c
+++ b/apple2/src/fn_fuji/fuji_appkey_write.c
@@ -3,10 +3,10 @@
 #include "fujinet-bus-apple2.h"
 #include <string.h>
 
-uint8_t fuji_appkey_write(uint16_t count, AppKeyWrite *buffer)
+// writes app-key, returns error status
+bool fuji_appkey_write(uint16_t count, AppKeyWrite *buffer)
 {
 	sp_error = sp_get_fuji_id();
-
 	if (sp_error <= 0) {
 		return false;
 	}
diff --git a/apple2/src/fn_fuji/fuji_base64_decode_compute.c b/apple2/src/fn_fuji/fuji_base64_decode_compute.c
index cb402ac..1ad903d 100644
--- a/apple2/src/fn_fuji/fuji_base64_decode_compute.c
+++ b/apple2/src/fn_fuji/fuji_base64_decode_compute.c
@@ -1,7 +1,7 @@
 #include <stdint.h>
 #include "fujinet-fuji.h"
 
-uint8_t fuji_base64_decode_compute()
+bool fuji_base64_decode_compute()
 {
-    return 1;
+    return true;
 }
diff --git a/apple2/src/fn_fuji/fuji_base64_decode_input.c b/apple2/src/fn_fuji/fuji_base64_decode_input.c
index 45c79fa..ef5a865 100644
--- a/apple2/src/fn_fuji/fuji_base64_decode_input.c
+++ b/apple2/src/fn_fuji/fuji_base64_decode_input.c
@@ -1,7 +1,7 @@
 #include <stdint.h>
 #include "fujinet-fuji.h"
 
-uint8_t fuji_base64_decode_input(char *s, uint16_t len)
+bool fuji_base64_decode_input(char *s, uint16_t len)
 {
-    return 1;
+    return true;
 }
diff --git a/apple2/src/fn_fuji/fuji_base64_decode_length.c b/apple2/src/fn_fuji/fuji_base64_decode_length.c
index 2ac78db..1873762 100644
--- a/apple2/src/fn_fuji/fuji_base64_decode_length.c
+++ b/apple2/src/fn_fuji/fuji_base64_decode_length.c
@@ -1,7 +1,7 @@
 #include <stdint.h>
 #include "fujinet-fuji.h"
 
-uint8_t fuji_base64_decode_length(unsigned long *len)
+bool fuji_base64_decode_length(unsigned long *len)
 {
-    return 1;
+    return true;
 }
diff --git a/apple2/src/fn_fuji/fuji_base64_decode_output.c b/apple2/src/fn_fuji/fuji_base64_decode_output.c
index 005ef36..302bffb 100644
--- a/apple2/src/fn_fuji/fuji_base64_decode_output.c
+++ b/apple2/src/fn_fuji/fuji_base64_decode_output.c
@@ -1,7 +1,7 @@
 #include <stdint.h>
 #include "fujinet-fuji.h"
 
-uint8_t fuji_base64_decode_output(char *s, uint16_t len)
+bool fuji_base64_decode_output(char *s, uint16_t len)
 {
-    return 1;
+    return true;
 }
diff --git a/apple2/src/fn_fuji/fuji_base64_encode_compute.c b/apple2/src/fn_fuji/fuji_base64_encode_compute.c
index 3c1bc99..e90a655 100644
--- a/apple2/src/fn_fuji/fuji_base64_encode_compute.c
+++ b/apple2/src/fn_fuji/fuji_base64_encode_compute.c
@@ -3,10 +3,10 @@
 #include "fujinet-fuji.h"
 #include "fujinet-bus-apple2.h"
 
-uint8_t fuji_base64_encode_compute()
+bool fuji_base64_encode_compute()
 {
     // send CTRL command: 0xCF
     // PAYLOAD: N/A
 
-    return sp_control(0, 0xCF);
+    return sp_control(0, 0xCF) == 0;
 }
diff --git a/apple2/src/fn_fuji/fuji_base64_encode_input.c b/apple2/src/fn_fuji/fuji_base64_encode_input.c
index b34bd5f..9585294 100644
--- a/apple2/src/fn_fuji/fuji_base64_encode_input.c
+++ b/apple2/src/fn_fuji/fuji_base64_encode_input.c
@@ -4,7 +4,7 @@
 #include "fujinet-fuji.h"
 #include "fujinet-bus-apple2.h"
 
-uint8_t fuji_base64_encode_input(char *s, uint16_t len)
+bool fuji_base64_encode_input(char *s, uint16_t len)
 {
     // send CTRL command: 0xD0
     // PAYLOAD:
@@ -13,6 +13,6 @@ uint8_t fuji_base64_encode_input(char *s, uint16_t len)
 
     if (len > MAX_DATA_LEN) return 1;
     strncpy(sp_payload, s, len);
-    return sp_control(0, 0xD0);
+    return sp_control(0, 0xD0) == 0;
 
 }
diff --git a/apple2/src/fn_fuji/fuji_base64_encode_length.c b/apple2/src/fn_fuji/fuji_base64_encode_length.c
index ef7529f..4b707ac 100644
--- a/apple2/src/fn_fuji/fuji_base64_encode_length.c
+++ b/apple2/src/fn_fuji/fuji_base64_encode_length.c
@@ -3,15 +3,7 @@
 #include "fujinet-fuji.h"
 #include "fujinet-bus-apple2.h"
 
-uint8_t fuji_base64_encode_length(unsigned long *len)
+bool fuji_base64_encode_length(unsigned long *len)
 {
-    // send STATUS command: 0xCE
-    // Return has length in first 2 bytes of payload
-
-    // TODO: how do we detect an error status coming back rather than data returned?
-
-    uint16_t length = sp_payload[0] | (sp_payload[1] << 8);
-    *len = length;
-
-    return 0;
+    return true;
 }
diff --git a/apple2/src/fn_fuji/fuji_base64_encode_output.c b/apple2/src/fn_fuji/fuji_base64_encode_output.c
index ee83db2..0d57429 100644
--- a/apple2/src/fn_fuji/fuji_base64_encode_output.c
+++ b/apple2/src/fn_fuji/fuji_base64_encode_output.c
@@ -1,7 +1,7 @@
 #include <stdint.h>
 #include "fujinet-fuji.h"
 
-uint8_t fuji_base64_encode_output(char *s, uint16_t len)
+bool fuji_base64_encode_output(char *s, uint16_t len)
 {
-    return 1;
+    return true;
 }
diff --git a/apple2/src/fn_fuji/fuji_hash_compute.c b/apple2/src/fn_fuji/fuji_hash_compute.c
index c6ea7b2..fc89f77 100644
--- a/apple2/src/fn_fuji/fuji_hash_compute.c
+++ b/apple2/src/fn_fuji/fuji_hash_compute.c
@@ -1,7 +1,7 @@
 #include <stdint.h>
 #include "fujinet-fuji.h"
 
-uint8_t fuji_hash_compute(uint8_t type)
+bool fuji_hash_compute(uint8_t type)
 {
-    return 0;
+    return true;
 }
diff --git a/apple2/src/fn_fuji/fuji_hash_input.c b/apple2/src/fn_fuji/fuji_hash_input.c
index 14d82d4..440ffb7 100644
--- a/apple2/src/fn_fuji/fuji_hash_input.c
+++ b/apple2/src/fn_fuji/fuji_hash_input.c
@@ -1,7 +1,7 @@
 #include <stdint.h>
 #include "fujinet-fuji.h"
 
-uint8_t fuji_hash_input(char *s, uint16_t len)
+bool fuji_hash_input(char *s, uint16_t len)
 {
-    return 0;
+    return true;
 }
diff --git a/apple2/src/fn_fuji/fuji_hash_length.c b/apple2/src/fn_fuji/fuji_hash_length.c
index dba93b5..81b16bb 100644
--- a/apple2/src/fn_fuji/fuji_hash_length.c
+++ b/apple2/src/fn_fuji/fuji_hash_length.c
@@ -1,7 +1,7 @@
 #include <stdint.h>
 #include "fujinet-fuji.h"
 
-uint8_t fuji_hash_length(uint8_t mode)
+bool fuji_hash_length(uint8_t mode)
 {
-    return 0;
+    return true;
 }
diff --git a/apple2/src/fn_fuji/fuji_hash_output.c b/apple2/src/fn_fuji/fuji_hash_output.c
index 9f3e622..bcd5c48 100644
--- a/apple2/src/fn_fuji/fuji_hash_output.c
+++ b/apple2/src/fn_fuji/fuji_hash_output.c
@@ -1,7 +1,7 @@
 #include <stdint.h>
 #include "fujinet-fuji.h"
 
-uint8_t fuji_hash_output(uint8_t output_type, char *s, uint16_t len)
+bool fuji_hash_output(uint8_t output_type, char *s, uint16_t len)
 {
-    return 0;
+    return true;
 }
diff --git a/atari/src/fn_fuji/fuji_appkey_open_read.s b/atari/src/fn_fuji/fuji_appkey_open_read.s
index 6d1a141..e797f2a 100644
--- a/atari/src/fn_fuji/fuji_appkey_open_read.s
+++ b/atari/src/fn_fuji/fuji_appkey_open_read.s
@@ -2,7 +2,7 @@
         .export         _fuji_appkey_read
 
         .import         _bus
-        .import         _fuji_error
+        .import         _fuji_success
         .import         copy_fuji_cmd_data
         .import         popa, popax
 
@@ -11,7 +11,7 @@
         .include        "device.inc"
         .include        "fujinet-fuji.inc"
 
-; uint8_t fuji_appkey_open(AppKeyOpen *buffer);
+; bool fuji_appkey_open(AppKeyOpen *buffer);
 ;
 _fuji_appkey_open:
         axinto  tmp7
@@ -23,10 +23,10 @@ ak_common:
         mwa     tmp7, IO_DCB::dbuflo
 
         jsr     _bus
-        jmp     _fuji_error
+        jmp     _fuji_success
 
 
-; uint8_t fuji_appkey_read(AppKeyRead *buffer);
+; bool fuji_appkey_read(AppKeyRead *buffer);
 ;
 _fuji_appkey_read:
         axinto  tmp7                    ; buffer location
diff --git a/atari/src/fn_fuji/fuji_appkey_write.s b/atari/src/fn_fuji/fuji_appkey_write.s
index 0ca4315..1e2d35d 100644
--- a/atari/src/fn_fuji/fuji_appkey_write.s
+++ b/atari/src/fn_fuji/fuji_appkey_write.s
@@ -1,7 +1,7 @@
         .export         _fuji_appkey_write
 
         .import         _bus
-        .import         _fuji_error
+        .import         _fuji_success
         .import         copy_fuji_cmd_data
         .import         popa, popax
 
@@ -10,8 +10,9 @@
         .include        "device.inc"
         .include        "fujinet-fuji.inc"
 
-; uint8_t fuji_appkey_write(uint16_t count, AppKeyWrite *buffer);
+; bool fuji_appkey_write(uint16_t count, AppKeyWrite *buffer);
 ;
+; NOTE: in other implementations there's a check to keep count maxed at 64 bytes
 .proc _fuji_appkey_write
         axinto  tmp7                    ; save buffer address
 
@@ -24,7 +25,7 @@
         stx     IO_DCB::daux2
 
         jsr     _bus
-        jmp     _fuji_error
+        jmp     _fuji_success
 .endproc
 
 .rodata
diff --git a/atari/src/fn_fuji/fuji_base64_xxcode_compute.s b/atari/src/fn_fuji/fuji_base64_xxcode_compute.s
index 016001c..4f4a234 100644
--- a/atari/src/fn_fuji/fuji_base64_xxcode_compute.s
+++ b/atari/src/fn_fuji/fuji_base64_xxcode_compute.s
@@ -3,14 +3,14 @@
 
         .import         copy_fuji_cmd_data
         .import         _bus
-        .import         _fuji_error
+        .import         _fuji_success
         .import         popa, popax
 
         .include        "zp.inc"
         .include        "macros.inc"
         .include        "device.inc"
 
-; uint8_t fuji_base64_decode_compute();
+; bool fuji_base64_decode_compute();
 ;
 _fuji_base64_decode_compute:
         setax   #t_fuji_base64_decode_compute
@@ -19,9 +19,9 @@ c_common:
         jsr     copy_fuji_cmd_data
         mva     #$03, IO_DCB::dtimlo
         jsr     _bus
-        jmp     _fuji_error
+        jmp     _fuji_success
 
-; uint8_t fuji_base64_encode_compute();
+; bool fuji_base64_encode_compute();
 ;
 _fuji_base64_encode_compute:
         setax   #t_fuji_base64_encode_compute
diff --git a/atari/src/fn_fuji/fuji_base64_xxcode_io.s b/atari/src/fn_fuji/fuji_base64_xxcode_io.s
index 3a2e3a1..7f4962e 100644
--- a/atari/src/fn_fuji/fuji_base64_xxcode_io.s
+++ b/atari/src/fn_fuji/fuji_base64_xxcode_io.s
@@ -11,28 +11,28 @@
         .include        "macros.inc"
         .include        "device.inc"
 
-; uint8_t fuji_base64_decode_input(char *s, uint16_t len);
+; bool fuji_base64_decode_input(char *s, uint16_t len);
 ;
 _fuji_base64_decode_input:
         axinto  tmp7                    ; len in tmp7/8
         setax   #t_fuji_base64_decode_input
         jmp     io_common
 
-; uint8_t fuji_base64_decode_output(char *s, uint16_t len);
+; bool fuji_base64_decode_output(char *s, uint16_t len);
 ;
 _fuji_base64_decode_output:
         axinto  tmp7                    ; len in tmp7/8
         setax   #t_fuji_base64_decode_output
         jmp     io_common
 
-; uint8_t fuji_base64_encode_input(char *s, uint16_t len);
+; bool fuji_base64_encode_input(char *s, uint16_t len);
 ;
 _fuji_base64_encode_input:
         axinto  tmp7                    ; len in tmp7/8
         setax   #t_fuji_base64_encode_input
         jmp     io_common
 
-; uint8_t fuji_base64_encode_output(char *s, uint16_t len);
+; bool fuji_base64_encode_output(char *s, uint16_t len);
 ;
 _fuji_base64_encode_output:
         axinto  tmp7                    ; len in tmp7/8
diff --git a/atari/src/fn_fuji/fuji_base64_xxcode_length.s b/atari/src/fn_fuji/fuji_base64_xxcode_length.s
index f97d6a6..fd2cfbf 100644
--- a/atari/src/fn_fuji/fuji_base64_xxcode_length.s
+++ b/atari/src/fn_fuji/fuji_base64_xxcode_length.s
@@ -3,14 +3,14 @@
 
         .import         copy_fuji_cmd_data
         .import         _bus
-        .import         _fuji_error
+        .import         _fuji_success
         .import         popa, popax
 
         .include        "zp.inc"
         .include        "macros.inc"
         .include        "device.inc"
 
-; uint8_t fuji_base64_decode_length(unsigned long *len);
+; bool fuji_base64_decode_length(unsigned long *len);
 ;
 _fuji_base64_decode_length:
         axinto   tmp7                   ; pointer to len in tmp7/8
@@ -22,9 +22,9 @@ de_common:
         mwa     tmp7, IO_DCB::dbuflo
         mva     #$03, IO_DCB::dtimlo
         jsr     _bus
-        jmp     _fuji_error
+        jmp     _fuji_success
 
-; uint8_t fuji_base64_encode_length(unsigned long *len);
+; bool fuji_base64_encode_length(unsigned long *len);
 ;
 _fuji_base64_encode_length:
         axinto  tmp7                   ; pointer to len in tmp7/8
diff --git a/atari/src/fn_fuji/fuji_crypto_common.s b/atari/src/fn_fuji/fuji_crypto_common.s
index 9b0f9bf..221e5cf 100644
--- a/atari/src/fn_fuji/fuji_crypto_common.s
+++ b/atari/src/fn_fuji/fuji_crypto_common.s
@@ -1,7 +1,7 @@
         .export     io_common
 
         .import     _bus
-        .import     _fuji_error
+        .import     _fuji_success
         .import     copy_fuji_cmd_data
         .import     popax
 
@@ -24,5 +24,5 @@
         stx     IO_DCB::dbufhi
 
         jsr     _bus
-        jmp     _fuji_error
+        jmp     _fuji_success
 .endproc
diff --git a/atari/src/fn_fuji/fuji_hash_compute.s b/atari/src/fn_fuji/fuji_hash_compute.s
index 89b0496..2f1acdf 100644
--- a/atari/src/fn_fuji/fuji_hash_compute.s
+++ b/atari/src/fn_fuji/fuji_hash_compute.s
@@ -1,7 +1,7 @@
         .export         _fuji_hash_compute
 
         .import         _bus
-        .import         _fuji_error
+        .import         _fuji_success
         .import         copy_fuji_cmd_data
         .import         popa, popax
 
@@ -9,7 +9,7 @@
         .include        "macros.inc"
         .include        "device.inc"
 
-; uint8_t fuji_hash_compute(uint8_t type);
+; bool fuji_hash_compute(uint8_t type);
 ;
 .proc _fuji_hash_compute
         sta     tmp7                    ; hash type, one of HashType. No validation done though
@@ -20,7 +20,7 @@
         mva     tmp7, IO_DCB::daux1
         mva     #$03, IO_DCB::dtimlo
         jsr     _bus
-        jmp     _fuji_error
+        jmp     _fuji_success
 .endproc
 
 .rodata
diff --git a/atari/src/fn_fuji/fuji_hash_input.s b/atari/src/fn_fuji/fuji_hash_input.s
index 20097ec..2eff195 100644
--- a/atari/src/fn_fuji/fuji_hash_input.s
+++ b/atari/src/fn_fuji/fuji_hash_input.s
@@ -6,7 +6,7 @@
         .include        "zp.inc"
         .include        "macros.inc"
 
-; uint8_t fuji_hash_input(char *s, uint16_t len);
+; bool fuji_hash_input(char *s, uint16_t len);
 ;
 .proc _fuji_hash_input
         axinto  tmp7                    ; len in tmp7/8
diff --git a/atari/src/fn_fuji/fuji_hash_length.s b/atari/src/fn_fuji/fuji_hash_length.s
index fac7427..4ee1c1c 100644
--- a/atari/src/fn_fuji/fuji_hash_length.s
+++ b/atari/src/fn_fuji/fuji_hash_length.s
@@ -1,7 +1,7 @@
         .export         _fuji_hash_length
 
         .import         _bus
-        .import         _fuji_error
+        .import         _fuji_success
         .import         copy_fuji_cmd_data
         .import         popa, popax
 
@@ -9,7 +9,7 @@
         .include        "macros.inc"
         .include        "device.inc"
 
-; uint8_t fuji_hash_length(uint8_t type);
+; bool fuji_hash_length(uint8_t type);
 ;
 .proc _fuji_hash_length
         sta     tmp7                            ; hash type, one of HashType. No validation done though
@@ -20,7 +20,7 @@
         mva     #$03, IO_DCB::dtimlo
 
         jsr     _bus
-        jmp     _fuji_error
+        jmp     _fuji_success
 .endproc
 
 .rodata
diff --git a/atari/src/fn_fuji/fuji_hash_output.s b/atari/src/fn_fuji/fuji_hash_output.s
index b763599..c8d85d5 100644
--- a/atari/src/fn_fuji/fuji_hash_output.s
+++ b/atari/src/fn_fuji/fuji_hash_output.s
@@ -1,7 +1,7 @@
         .export         _fuji_hash_output
 
         .import         _bus
-        .import         _fuji_error
+        .import         _fuji_success
         .import         copy_fuji_cmd_data
         .import         popa, popax
 
@@ -9,7 +9,7 @@
         .include        "macros.inc"
         .include        "device.inc"
 
-; uint8_t fuji_hash_output(uint8_t output_type, char *s, uint16_t len);
+; bool fuji_hash_output(uint8_t output_type, char *s, uint16_t len);
 ;
 .proc _fuji_hash_output
         axinto  tmp7                    ; len pointer
@@ -28,7 +28,7 @@
         sta     IO_DCB::daux1
 
         jsr     _bus
-        jmp     _fuji_error
+        jmp     _fuji_success
 .endproc
 
 .rodata
diff --git a/commodore/src/fn_fuji/fuji_appkey_open.c b/commodore/src/fn_fuji/fuji_appkey_open.c
index a9a27e5..21ec5eb 100644
--- a/commodore/src/fn_fuji/fuji_appkey_open.c
+++ b/commodore/src/fn_fuji/fuji_appkey_open.c
@@ -2,7 +2,7 @@
 #include <stdint.h>
 #include "fujinet-fuji.h"
 
-uint8_t fuji_appkey_open(AppKeyOpen *buffer)
+bool fuji_appkey_open(AppKeyOpen *buffer)
 {
 	return 0;
 }
diff --git a/commodore/src/fn_fuji/fuji_appkey_read.c b/commodore/src/fn_fuji/fuji_appkey_read.c
index 949313a..01a4ace 100644
--- a/commodore/src/fn_fuji/fuji_appkey_read.c
+++ b/commodore/src/fn_fuji/fuji_appkey_read.c
@@ -2,7 +2,7 @@
 #include <stdint.h>
 #include "fujinet-fuji.h"
 
-uint8_t fuji_appkey_read(AppKeyRead *buffer)
+bool fuji_appkey_read(AppKeyRead *buffer)
 {
 	return 0;
 }
diff --git a/commodore/src/fn_fuji/fuji_appkey_write.c b/commodore/src/fn_fuji/fuji_appkey_write.c
index 27314bb..81e83cd 100644
--- a/commodore/src/fn_fuji/fuji_appkey_write.c
+++ b/commodore/src/fn_fuji/fuji_appkey_write.c
@@ -2,7 +2,7 @@
 #include <stdint.h>
 #include "fujinet-fuji.h"
 
-uint8_t fuji_appkey_write(uint16_t count, AppKeyWrite *buffer)
+bool fuji_appkey_write(uint16_t count, AppKeyWrite *buffer)
 {
 	return 0;
 }
diff --git a/commodore/src/fn_fuji/fuji_base64_decode_compute.c b/commodore/src/fn_fuji/fuji_base64_decode_compute.c
index 7dea301..9908f1c 100644
--- a/commodore/src/fn_fuji/fuji_base64_decode_compute.c
+++ b/commodore/src/fn_fuji/fuji_base64_decode_compute.c
@@ -2,7 +2,7 @@
 #include <stdint.h>
 #include "fujinet-fuji.h"
 
-uint8_t fuji_base64_decode_compute()
+bool fuji_base64_decode_compute()
 {
 	return 0;
 }
diff --git a/commodore/src/fn_fuji/fuji_base64_decode_input.c b/commodore/src/fn_fuji/fuji_base64_decode_input.c
index 24a0cb0..c2975e9 100644
--- a/commodore/src/fn_fuji/fuji_base64_decode_input.c
+++ b/commodore/src/fn_fuji/fuji_base64_decode_input.c
@@ -2,7 +2,7 @@
 #include <stdint.h>
 #include "fujinet-fuji.h"
 
-uint8_t fuji_base64_decode_input(char *s, uint16_t len)
+bool fuji_base64_decode_input(char *s, uint16_t len)
 {
 	return 0;
 }
diff --git a/commodore/src/fn_fuji/fuji_base64_decode_length.c b/commodore/src/fn_fuji/fuji_base64_decode_length.c
index 20dce40..7c588f5 100644
--- a/commodore/src/fn_fuji/fuji_base64_decode_length.c
+++ b/commodore/src/fn_fuji/fuji_base64_decode_length.c
@@ -2,7 +2,7 @@
 #include <stdint.h>
 #include "fujinet-fuji.h"
 
-uint8_t fuji_base64_decode_length(unsigned long *len)
+bool fuji_base64_decode_length(unsigned long *len)
 {
 	return 0;
 }
diff --git a/commodore/src/fn_fuji/fuji_base64_decode_output.c b/commodore/src/fn_fuji/fuji_base64_decode_output.c
index beb8718..c2e42ec 100644
--- a/commodore/src/fn_fuji/fuji_base64_decode_output.c
+++ b/commodore/src/fn_fuji/fuji_base64_decode_output.c
@@ -2,7 +2,7 @@
 #include <stdint.h>
 #include "fujinet-fuji.h"
 
-uint8_t fuji_base64_decode_output(char *s, uint16_t len)
+bool fuji_base64_decode_output(char *s, uint16_t len)
 {
 	return 0;
 }
diff --git a/commodore/src/fn_fuji/fuji_base64_encode_compute.c b/commodore/src/fn_fuji/fuji_base64_encode_compute.c
index 089273c..1eb69e3 100644
--- a/commodore/src/fn_fuji/fuji_base64_encode_compute.c
+++ b/commodore/src/fn_fuji/fuji_base64_encode_compute.c
@@ -2,7 +2,7 @@
 #include <stdint.h>
 #include "fujinet-fuji.h"
 
-uint8_t fuji_base64_encode_compute()
+bool fuji_base64_encode_compute()
 {
 	return 0;
 }
diff --git a/commodore/src/fn_fuji/fuji_base64_encode_input.c b/commodore/src/fn_fuji/fuji_base64_encode_input.c
index 70ff6fb..2bc0a68 100644
--- a/commodore/src/fn_fuji/fuji_base64_encode_input.c
+++ b/commodore/src/fn_fuji/fuji_base64_encode_input.c
@@ -2,7 +2,7 @@
 #include <stdint.h>
 #include "fujinet-fuji.h"
 
-uint8_t fuji_base64_encode_input(char *s, uint16_t len)
+bool fuji_base64_encode_input(char *s, uint16_t len)
 {
 	return 0;
 }
diff --git a/commodore/src/fn_fuji/fuji_base64_encode_length.c b/commodore/src/fn_fuji/fuji_base64_encode_length.c
index 0826879..e613b2c 100644
--- a/commodore/src/fn_fuji/fuji_base64_encode_length.c
+++ b/commodore/src/fn_fuji/fuji_base64_encode_length.c
@@ -2,7 +2,7 @@
 #include <stdint.h>
 #include "fujinet-fuji.h"
 
-uint8_t fuji_base64_encode_length(unsigned long *len)
+bool fuji_base64_encode_length(unsigned long *len)
 {
 	return 0;
 }
diff --git a/commodore/src/fn_fuji/fuji_base64_encode_output.c b/commodore/src/fn_fuji/fuji_base64_encode_output.c
index 0d9bf5f..dee6287 100644
--- a/commodore/src/fn_fuji/fuji_base64_encode_output.c
+++ b/commodore/src/fn_fuji/fuji_base64_encode_output.c
@@ -2,7 +2,7 @@
 #include <stdint.h>
 #include "fujinet-fuji.h"
 
-uint8_t fuji_base64_encode_output(char *s, uint16_t len)
+bool fuji_base64_encode_output(char *s, uint16_t len)
 {
 	return 0;
 }
diff --git a/commodore/src/fn_fuji/fuji_hash_compute.c b/commodore/src/fn_fuji/fuji_hash_compute.c
index 8b278dc..99affc0 100644
--- a/commodore/src/fn_fuji/fuji_hash_compute.c
+++ b/commodore/src/fn_fuji/fuji_hash_compute.c
@@ -2,7 +2,7 @@
 #include <stdint.h>
 #include "fujinet-fuji.h"
 
-uint8_t fuji_hash_compute(uint8_t type)
+bool fuji_hash_compute(uint8_t type)
 {
 	return 0;
 }
diff --git a/commodore/src/fn_fuji/fuji_hash_input.c b/commodore/src/fn_fuji/fuji_hash_input.c
index b2530f0..0d2e8fb 100644
--- a/commodore/src/fn_fuji/fuji_hash_input.c
+++ b/commodore/src/fn_fuji/fuji_hash_input.c
@@ -2,7 +2,7 @@
 #include <stdint.h>
 #include "fujinet-fuji.h"
 
-uint8_t fuji_hash_input(char *s, uint16_t len)
+bool fuji_hash_input(char *s, uint16_t len)
 {
 	return 0;
 }
diff --git a/commodore/src/fn_fuji/fuji_hash_length.c b/commodore/src/fn_fuji/fuji_hash_length.c
index 1200717..884d01c 100644
--- a/commodore/src/fn_fuji/fuji_hash_length.c
+++ b/commodore/src/fn_fuji/fuji_hash_length.c
@@ -2,7 +2,7 @@
 #include <stdint.h>
 #include "fujinet-fuji.h"
 
-uint8_t fuji_hash_length(uint8_t mode)
+bool fuji_hash_length(uint8_t mode)
 {
 	return 0;
 }
diff --git a/commodore/src/fn_fuji/fuji_hash_output.c b/commodore/src/fn_fuji/fuji_hash_output.c
index 1ae580e..a0d09e8 100644
--- a/commodore/src/fn_fuji/fuji_hash_output.c
+++ b/commodore/src/fn_fuji/fuji_hash_output.c
@@ -2,7 +2,7 @@
 #include <stdint.h>
 #include "fujinet-fuji.h"
 
-uint8_t fuji_hash_output(uint8_t output_type, char *s, uint16_t len)
+bool fuji_hash_output(uint8_t output_type, char *s, uint16_t len)
 {
 	return 0;
 }
diff --git a/fujinet-fuji.h b/fujinet-fuji.h
index 5c81778..318c88c 100644
--- a/fujinet-fuji.h
+++ b/fujinet-fuji.h
@@ -398,26 +398,41 @@ bool fuji_unmount_disk_image(uint8_t ds);
  */
 bool fuji_unmount_host_slot(uint8_t hs);
 
-// app key
-uint8_t fuji_appkey_open(AppKeyOpen *buffer);
-uint8_t fuji_appkey_read(AppKeyRead *buffer);
-uint8_t fuji_appkey_write(uint16_t count, AppKeyWrite *buffer);
+/*
+ * Opens the appkey ready for reading/writing from details in buffer
+ * @return ERROR status of request (i.e. true means there was an error)
+ */
+bool fuji_appkey_open(AppKeyOpen *buffer);
+
+/*
+ * Reads the appkey specified previously in open call.
+ * @return ERROR status of request (i.e. true means there was an error)
+ */
+bool fuji_appkey_read(AppKeyRead *buffer);
+
+/*
+ * Writes to the appkey specified previously in open call.
+ * @return ERROR status of request (i.e. true means there was an error)
+ */
+bool fuji_appkey_write(uint16_t count, AppKeyWrite *buffer);
 
 // Base64
-uint8_t fuji_base64_decode_compute();
-uint8_t fuji_base64_decode_input(char *s, uint16_t len);
-uint8_t fuji_base64_decode_length(unsigned long *len);
-uint8_t fuji_base64_decode_output(char *s, uint16_t len);
+// ALL RETURN VALUES ARE SUCCESS STATUS VALUE, i.e. true == success 
+bool fuji_base64_decode_compute();
+bool fuji_base64_decode_input(char *s, uint16_t len);
+bool fuji_base64_decode_length(unsigned long *len);
+bool fuji_base64_decode_output(char *s, uint16_t len);
 
-uint8_t fuji_base64_encode_compute();
-uint8_t fuji_base64_encode_input(char *s, uint16_t len);
-uint8_t fuji_base64_encode_length(unsigned long *len);
-uint8_t fuji_base64_encode_output(char *s, uint16_t len);
+bool fuji_base64_encode_compute();
+bool fuji_base64_encode_input(char *s, uint16_t len);
+bool fuji_base64_encode_length(unsigned long *len);
+bool fuji_base64_encode_output(char *s, uint16_t len);
 
 // Hash
-uint8_t fuji_hash_compute(uint8_t type);
-uint8_t fuji_hash_input(char *s, uint16_t len);
-uint8_t fuji_hash_length(uint8_t mode);
-uint8_t fuji_hash_output(uint8_t output_type, char *s, uint16_t len);
+// ALL RETURN VALUES ARE SUCCESS STATUS VALUE, i.e. true == success 
+bool fuji_hash_compute(uint8_t type);
+bool fuji_hash_input(char *s, uint16_t len);
+bool fuji_hash_length(uint8_t mode);
+bool fuji_hash_output(uint8_t output_type, char *s, uint16_t len);
 
 #endif /* FN_FUJI_H */
\ No newline at end of file
diff --git a/version.txt b/version.txt
index b38ebbf..0c89fc9 100644
--- a/version.txt
+++ b/version.txt
@@ -1 +1 @@
-3.0.4
\ No newline at end of file
+4.0.0
\ No newline at end of file