diff --git a/speculos/cxlib/nanosp-api-level-cx-15.elf b/speculos/cxlib/nanosp-api-level-cx-15.elf
new file mode 100755
index 00000000..332301e8
Binary files /dev/null and b/speculos/cxlib/nanosp-api-level-cx-15.elf differ
diff --git a/speculos/cxlib/nanox-api-level-cx-15.elf b/speculos/cxlib/nanox-api-level-cx-15.elf
new file mode 100755
index 00000000..f7a84e08
Binary files /dev/null and b/speculos/cxlib/nanox-api-level-cx-15.elf differ
diff --git a/speculos/cxlib/stax-api-level-cx-15.elf b/speculos/cxlib/stax-api-level-cx-15.elf
new file mode 100755
index 00000000..65a04356
Binary files /dev/null and b/speculos/cxlib/stax-api-level-cx-15.elf differ
diff --git a/speculos/fonts/nanosp-fonts-15.bin b/speculos/fonts/nanosp-fonts-15.bin
new file mode 100644
index 00000000..180a0f81
Binary files /dev/null and b/speculos/fonts/nanosp-fonts-15.bin differ
diff --git a/speculos/fonts/nanox-fonts-15.bin b/speculos/fonts/nanox-fonts-15.bin
new file mode 100644
index 00000000..94949885
Binary files /dev/null and b/speculos/fonts/nanox-fonts-15.bin differ
diff --git a/speculos/fonts/stax-fonts-15.bin b/speculos/fonts/stax-fonts-15.bin
new file mode 100644
index 00000000..4dd8545a
Binary files /dev/null and b/speculos/fonts/stax-fonts-15.bin differ
diff --git a/speculos/main.py b/speculos/main.py
index da531853..f1413157 100644
--- a/speculos/main.py
+++ b/speculos/main.py
@@ -139,7 +139,26 @@ def get_cx_infos(app_path):
     return sh_offset, sh_size, sh_load, cx_ram_size, cx_ram_load
 
 
-def run_qemu(s1: socket.socket, s2: socket.socket, args: argparse.Namespace) -> int:
+def get_elf_fonts_size(app_path):
+    with open(app_path, 'rb') as fp:
+        elf = ELFFile(fp)
+        text = elf.get_section_by_name('.text')
+        for seg in elf.iter_segments():
+            if seg['p_type'] != 'PT_LOAD':
+                continue
+            if seg.section_in_segment(text):
+                break
+        else:
+            raise RuntimeError("No program header with text section!")
+        symtab = elf.get_section_by_name('.symtab')
+        bagl_fonts_symbol = symtab.get_symbol_by_name('C_bagl_fonts')
+        if bagl_fonts_symbol is not None:
+            return bagl_fonts_symbol[0]['st_size']
+
+    return 0
+
+
+def run_qemu(s1: socket.socket, s2: socket.socket, args: argparse.Namespace, is_bagl: bool) -> int:
     argv = ['qemu-arm-static']
 
     if args.debug:
@@ -170,13 +189,12 @@ def run_qemu(s1: socket.socket, s2: socket.socket, args: argparse.Namespace) ->
     else:
         logger.warn(f"Cx lib {cxlib_filepath} not found")
 
-    if args.model == "stax":
-        fonts_filepath = f"/fonts/{args.model}-fonts-{args.apiLevel}.bin"
-        fonts = pkg_resources.resource_filename(__name__, fonts_filepath)
-        if os.path.exists(fonts):
-            argv += ['-f', fonts]
-        else:
-            logger.warn(f"Fonts {fonts_filepath} not found")
+    fonts_filepath = f"/fonts/{args.model}-fonts-{args.apiLevel}.bin"
+    fonts = pkg_resources.resource_filename(__name__, fonts_filepath)
+    if os.path.exists(fonts):
+        argv += ['-f', fonts]
+    elif not is_bagl:
+        logger.warn(f"Fonts {fonts_filepath} not found")
 
     extra_ram = ''
     app_path = getattr(args, 'app.elf')
@@ -185,6 +203,7 @@ def run_qemu(s1: socket.socket, s2: socket.socket, args: argparse.Namespace) ->
         load_offset, load_size, stack, stack_size, ram_addr, ram_size, \
             text_load_addr, svc_call_address, svc_cx_call_address, \
             fonts_addr, fonts_size = get_elf_infos(lib_path)
+
         # Since binaries loaded as libs could also declare extra RAM page(s), collect them all
         if (ram_addr, ram_size) != (0, 0):
             arg = f'{ram_addr:#x}:{ram_size:#x}'
@@ -317,6 +336,7 @@ def main(prog=None) -> int:
 
     # Init model and api_level if not specified from app elf metadata
     app_path = getattr(args, 'app.elf')
+    is_bagl = get_elf_fonts_size(app_path) != 0
     metadata = get_elf_ledger_metadata(app_path)
     if not args.model:
         if "target" not in metadata:
@@ -473,13 +493,14 @@ def main(prog=None) -> int:
 
     s1, s2 = socket.socketpair()
 
-    qemu_pid = run_qemu(s1, s2, args)
+    qemu_pid = run_qemu(s1, s2, args, is_bagl)
     s1.close()
 
     apdu = apdu_server.ApduServer(host="0.0.0.0", port=args.apdu_port)
     seph = seproxyhal.SeProxyHal(
         s2,
         model=args.model,
+        is_bagl=is_bagl,
         automation=automation_path,
         automation_server=automation_server,
         transport=args.usb)
@@ -521,7 +542,7 @@ def main(prog=None) -> int:
     display_args = DisplayArgs(args.color, args.model, args.ontop, rendering,
                                args.keymap, zoom, x, y)
     server_args = ServerArgs(apdu, apirun, button, finger, seph, vnc)
-    screen_notifier = ScreenNotifier(display_args, server_args)
+    screen_notifier = ScreenNotifier(display_args, server_args, is_bagl)
 
     if apirun is not None:
         assert automation_server is not None
diff --git a/speculos/mcu/display.py b/speculos/mcu/display.py
index a2749c27..e5f232f0 100644
--- a/speculos/mcu/display.py
+++ b/speculos/mcu/display.py
@@ -272,7 +272,7 @@ class DisplayNotifier(ABC):
       through VNC if activated.
     """
 
-    def __init__(self, display_args: DisplayArgs, server_args: ServerArgs) -> None:
+    def __init__(self, display_args: DisplayArgs, server_args: ServerArgs, is_bagl: bool) -> None:
         # TODO: this should be Dict[int, IODevice], but in QtScreen, it is
         #       a QSocketNotifier, which has a completely different interface
         #       and is not used in the same way in the mcu/screen.py module.
@@ -280,10 +280,11 @@ def __init__(self, display_args: DisplayArgs, server_args: ServerArgs) -> None:
         self._server_args = server_args
         self._display_args = display_args
         self._display: Display
+        self.is_bagl = is_bagl
         self.__init_notifiers()
 
     def _set_display_class(self, display_class: type):
-        self._display = display_class(self._display_args, self._server_args)
+        self._display = display_class(self._display_args, self._server_args, self.is_bagl)
 
     @property
     def display(self) -> Display:
diff --git a/speculos/mcu/headless.py b/speculos/mcu/headless.py
index f0df659b..61a349c8 100644
--- a/speculos/mcu/headless.py
+++ b/speculos/mcu/headless.py
@@ -11,12 +11,12 @@
 
 
 class Headless(Display):
-    def __init__(self, display: DisplayArgs, server: ServerArgs) -> None:
+    def __init__(self, display: DisplayArgs, server: ServerArgs, is_bagl: bool) -> None:
         super().__init__(display, server)
 
         self.m = HeadlessPaintWidget(self.model, server.vnc)
         self._gl: GraphicLibrary
-        if display.model != "stax":
+        if is_bagl:
             self._gl = bagl.Bagl(self.m, MODELS[self.model].screen_size, self.model)
         else:
             self._gl = nbgl.NBGL(self.m, MODELS[self.model].screen_size, self.model)
@@ -67,8 +67,8 @@ def _redraw(self) -> None:
 
 class HeadlessNotifier(DisplayNotifier):
 
-    def __init__(self, display_args: DisplayArgs, server_args: ServerArgs) -> None:
-        super().__init__(display_args, server_args)
+    def __init__(self, display_args: DisplayArgs, server_args: ServerArgs, is_bagl: bool) -> None:
+        super().__init__(display_args, server_args, is_bagl)
         self._set_display_class(Headless)
 
     def run(self) -> None:
diff --git a/speculos/mcu/nbgl.py b/speculos/mcu/nbgl.py
index 944a2ec4..5fbd4df4 100644
--- a/speculos/mcu/nbgl.py
+++ b/speculos/mcu/nbgl.py
@@ -47,7 +47,7 @@ def __init__(self,
         self.logger = logging.getLogger("NBGL")
 
     def __assert_area(self, area) -> None:
-        if area.y0 % 4 or area.height % 4:
+        if self.model == "stax" and (area.y0 % 4 or area.height % 4):
             raise AssertionError("X(%d) or height(%d) not 4 aligned " % (area.y0, area.height))
         if area.x0 > self.SCREEN_WIDTH or (area.x0+area.width) > self.SCREEN_WIDTH:
             raise AssertionError("left edge (%d) or right edge (%d) out of screen" % (area.x0, (area.x0 + area.width)))
diff --git a/speculos/mcu/ocr.py b/speculos/mcu/ocr.py
index 1f03856e..12046a87 100644
--- a/speculos/mcu/ocr.py
+++ b/speculos/mcu/ocr.py
@@ -121,10 +121,11 @@ class OCR:
     MAX_BLANK_SPACE_NANO = 12
     MAX_BLANK_SPACE_STAX = 24
 
-    def __init__(self, model: str):
+    def __init__(self, model: str, is_bagl: bool):
         self.events: List[TextEvent] = []
         # Store the model of the device
         self.model = model
+        self.is_bagl = is_bagl
         # Maximum space for a letter to be considered part of the same word
         if model == "stax":
             self.max_blank_space = OCR.MAX_BLANK_SPACE_STAX
@@ -215,7 +216,7 @@ def analyze_bitmap(self, data: bytes) -> None:
         For older SKD versions, legacy behaviour is used: parsing internal
         fonts to find a matching bitmap.
         """
-        if self.model == "stax":
+        if not self.is_bagl:
             # Can be called via SephTag.NBGL_DRAW_IMAGE or SephTag.NBGL_DRAW_IMAGE_RLE
             # In both cases, data contains:
             # - area (sizeof(nbgl_area_t))
diff --git a/speculos/mcu/rle_custom.py b/speculos/mcu/rle_custom.py
index f98892d6..a251cb48 100755
--- a/speculos/mcu/rle_custom.py
+++ b/speculos/mcu/rle_custom.py
@@ -153,9 +153,8 @@ def values_to_bpp1(data):
         if bits != 7:
             output += bytes([byte])
 
-        nb_bytes = len(data)/8
-        if len(data) % 8:
-            nb_bytes += 1
+        nb_bytes = (len(data)+7)//8
+
         assert len(output) == nb_bytes
 
         return output
diff --git a/speculos/mcu/screen.py b/speculos/mcu/screen.py
index 9d00a69b..d99ef01a 100644
--- a/speculos/mcu/screen.py
+++ b/speculos/mcu/screen.py
@@ -28,9 +28,10 @@ def __init__(self, parent, model: str, pixel_size: int, vnc: Optional[VNC] = Non
         self.pixel_size = pixel_size
         self.mPixmap = QPixmap()
         self.vnc = vnc
+        self.updateRequested = False
 
     def paintEvent(self, event: QEvent):
-        if self.pixels:
+        if self.pixels and self.updateRequested:
             pixmap = QPixmap(self.size() / self.pixel_size)
             pixmap.fill(Qt.white)
             painter = QPainter(pixmap)
@@ -38,6 +39,7 @@ def paintEvent(self, event: QEvent):
             self._redraw(painter)
             self.mPixmap = pixmap
             self.pixels = {}
+            self.updateRequested = False
 
         qp = QPainter(self)
         copied_pixmap = self.mPixmap
@@ -53,6 +55,7 @@ def update(self,  # type: ignore[override]
                y: Optional[int] = None,
                w: Optional[int] = None,
                h: Optional[int] = None) -> bool:
+        self.updateRequested = True
         if x and y and w and h:
             QWidget.update(self, QRect(x, y, w, h))
         else:
@@ -192,16 +195,17 @@ def closeEvent(self, event: QEvent):
 
 
 class Screen(Display):
-    def __init__(self, display: DisplayArgs, server: ServerArgs) -> None:
+    def __init__(self, display: DisplayArgs, server: ServerArgs, is_bagl: bool) -> None:
         super().__init__(display, server)
         self.app: App
         self._gl: GraphicLibrary
+        self.is_bagl = is_bagl
 
-    def set_app(self, app: App) -> None:
+    def set_app(self, app: App, is_bagl: bool) -> None:
         self.app = app
         self.app.set_screen(self)
         model = self._display_args.model
-        if model != "stax":
+        if self.is_bagl:
             self._gl = bagl.Bagl(app.widget, MODELS[model].screen_size, model)
         else:
             self._gl = nbgl.NBGL(app.widget, MODELS[model].screen_size, model)
@@ -244,13 +248,13 @@ def screen_update(self) -> bool:
 
 
 class QtScreenNotifier(DisplayNotifier):
-    def __init__(self, display_args: DisplayArgs, server_args: ServerArgs) -> None:
+    def __init__(self, display_args: DisplayArgs, server_args: ServerArgs, is_bagl: bool) -> None:
         self._qapp = QApplication([])
-        super().__init__(display_args, server_args)
+        super().__init__(display_args, server_args, is_bagl)
         self._set_display_class(Screen)
         self._app_widget = App(self._qapp, display_args, server_args)
         assert isinstance(self.display, Screen)
-        self.display.set_app(self._app_widget)
+        self.display.set_app(self._app_widget, is_bagl)
 
     def _can_read(self, device: IODevice) -> None:
         try:
diff --git a/speculos/mcu/screen_text.py b/speculos/mcu/screen_text.py
index ea509b14..53a9acc1 100644
--- a/speculos/mcu/screen_text.py
+++ b/speculos/mcu/screen_text.py
@@ -100,12 +100,12 @@ def _redraw(self):
 
 
 class TextScreen(Display):
-    def __init__(self, display_args: DisplayArgs, server_args: ServerArgs) -> None:
+    def __init__(self, display_args: DisplayArgs, server_args: ServerArgs, is_bagl: bool) -> None:
         super().__init__(display_args, server_args)
 
         self.width, self.height = MODELS[display_args.model].screen_size
         self.m = TextWidget(self, display_args.model)
-        if display_args.model != "stax":
+        if is_bagl:
             self._gl = bagl.Bagl(self.m, MODELS[display_args.model].screen_size, display_args.model)
         else:
             raise NotImplementedError("This display can not emulate NBGL OS yet")
@@ -151,8 +151,8 @@ def get_keypress(self) -> bool:
 
 class TextScreenNotifier(DisplayNotifier):
 
-    def __init__(self, display_args: DisplayArgs, server_args: ServerArgs) -> None:
-        super().__init__(display_args, server_args)
+    def __init__(self, display_args: DisplayArgs, server_args: ServerArgs, _is_bagl: bool) -> None:
+        super().__init__(display_args, server_args, _is_bagl)
         self._set_display_class(TextScreen)
 
     def run(self) -> None:
diff --git a/speculos/mcu/seproxyhal.py b/speculos/mcu/seproxyhal.py
index 97a63383..86971e28 100644
--- a/speculos/mcu/seproxyhal.py
+++ b/speculos/mcu/seproxyhal.py
@@ -242,6 +242,7 @@ class SeProxyHal(IODevice):
     def __init__(self,
                  sock: socket,
                  model: str,
+                 is_bagl: bool,
                  automation: Optional[Automation] = None,
                  automation_server: Optional[BroadcastInterface] = None,
                  transport: str = 'hid'):
@@ -262,7 +263,7 @@ def __init__(self,
 
         self.usb = usb.USB(self.socket_helper.queue_packet, transport=transport)
 
-        self.ocr = OCR(model)
+        self.ocr = OCR(model, is_bagl)
 
         # A list of callback methods when an APDU response is received
         self.apdu_callbacks: List[Callable[[bytes], None]] = []
@@ -326,10 +327,10 @@ def can_read(self, screen: DisplayNotifier):
                     # Publish the new screenshot, we'll upload its associated events shortly
                     screen.display.gl.update_public_screenshot()
 
-                if screen.display.model != "stax" and screen.display.screen_update():
+                if not isinstance(screen.display.gl, NBGL) and screen.display.screen_update():
                     if screen.display.model in ["nanox", "nanosp"]:
                         self.events += self.ocr.get_events()
-                elif screen.display.model == "stax":
+                elif isinstance(screen.display.gl, NBGL):
                     self.events += self.ocr.get_events()
 
                 # Apply automation rules after having received a GENERAL_STATUS_LAST_COMMAND tag. It allows the
diff --git a/src/bolos/bagl.c b/src/bolos/bagl.c
index 04b2ab16..deaf3ce6 100644
--- a/src/bolos/bagl.c
+++ b/src/bolos/bagl.c
@@ -157,7 +157,7 @@ unsigned long sys_bagl_hal_draw_bitmap_within_rect(
     sys_io_seph_send(buf, len);
   }
 
-  return 0;
+  return 0x9000; // SWO_SUCCESS
 }
 
 unsigned long sys_screen_update(void)
diff --git a/src/bolos/fonts_info.c b/src/bolos/fonts_info.c
index 5000566b..ba42b193 100644
--- a/src/bolos/fonts_info.c
+++ b/src/bolos/fonts_info.c
@@ -12,8 +12,8 @@ typedef struct {
   uint32_t character;
 } BITMAP_CHAR;
 
-BITMAP_CHAR bitmap_char[MAX_BITMAP_CHAR];
-uint32_t nb_bitmap_char;
+static BITMAP_CHAR bitmap_char[MAX_BITMAP_CHAR];
+static uint32_t nb_bitmap_char;
 
 // Return the real addr depending on where the app was loaded
 static void *remap_addr(void *code, uint32_t addr, uint32_t text_load_addr)
@@ -190,7 +190,7 @@ void parse_fonts(void *code, unsigned long text_load_addr,
                  unsigned long fonts_addr, unsigned long fonts_size)
 {
   // Number of fonts stored at fonts_addr
-  uint32_t nb_fonts;
+  uint32_t nb_fonts = 0;
   uint32_t *fonts;
 
   nb_bitmap_char = 0;
@@ -203,15 +203,31 @@ void parse_fonts(void *code, unsigned long text_load_addr,
   case SDK_API_LEVEL_12:
   case SDK_API_LEVEL_13:
   case SDK_API_LEVEL_14:
+  case SDK_API_LEVEL_15:
     break;
   default:
     // Unsupported API_LEVEL, will not parse fonts!
     return;
   }
-  // On Stax, fonts are loaded at a known location
-  if (hw_model == MODEL_STAX) {
-    fonts = (void *)STAX_FONTS_ARRAY_ADDR;
-    nb_fonts = STAX_NB_FONTS;
+  // With NBGL apps, fonts are loaded at a known location, in the OS
+  if (fonts_size == 0) {
+    if (hw_model == MODEL_STAX) {
+      fonts = (void *)STAX_FONTS_ARRAY_ADDR;
+      if (sdk_version >= SDK_API_LEVEL_15) {
+        nb_fonts = STAX_NB_FONTS;
+      } else {
+        nb_fonts = STAX_NB_FONTS_LEVEL_14;
+      }
+    } else if (hw_model == MODEL_NANO_SP) {
+      fonts = (void *)NANOSP_FONTS_ARRAY_ADDR;
+      nb_fonts = NANO_NB_FONTS;
+    } else if (hw_model == MODEL_NANO_X) {
+      fonts = (void *)NANOX_FONTS_ARRAY_ADDR;
+      nb_fonts = NANO_NB_FONTS;
+    } else {
+      return;
+    }
+
   } else {
     fonts = remap_addr(code, fonts_addr, text_load_addr);
     nb_fonts = fonts_size / 4;
@@ -236,7 +252,7 @@ void parse_fonts(void *code, unsigned long text_load_addr,
 
   // Parse all those fonts and add bitmap/character pairs
   for (uint32_t i = 0; i < nb_fonts; i++) {
-    if (hw_model == MODEL_STAX) {
+    if (fonts_size == 0) {
       switch (sdk_version) {
       case SDK_API_LEVEL_12:
       case SDK_API_LEVEL_13:
diff --git a/src/bolos/nbgl.c b/src/bolos/nbgl.c
index fbf9b92c..7b05c1d8 100644
--- a/src/bolos/nbgl.c
+++ b/src/bolos/nbgl.c
@@ -148,10 +148,34 @@ unsigned long sys_nbgl_front_draw_img_file(nbgl_area_t *area, uint8_t *buffer,
 
 unsigned long sys_nbgl_get_font(unsigned int fontId)
 {
-  if (fontId >= STAX_NB_FONTS) {
-    return 0;
+  if (hw_model == MODEL_STAX) {
+    unsigned int maxNbFonts;
+    if (sdk_version >= SDK_API_LEVEL_15) {
+      maxNbFonts = STAX_NB_FONTS;
+    } else {
+      maxNbFonts = STAX_NB_FONTS_LEVEL_14;
+    }
+    if (fontId >= maxNbFonts) {
+      return 0;
+    } else {
+      return *((unsigned int *)(STAX_FONTS_ARRAY_ADDR + (4 * fontId)));
+    }
+  } else if (hw_model == MODEL_NANO_SP) {
+    fontId -= 8; // BAGL_FONT_OPEN_SANS_EXTRABOLD_11px_1bpp
+    if (fontId >= NANO_NB_FONTS) {
+      return 0;
+    } else {
+      return *((unsigned int *)(NANOSP_FONTS_ARRAY_ADDR + (4 * fontId)));
+    }
+  } else if (hw_model == MODEL_NANO_X) {
+    fontId -= 8; // BAGL_FONT_OPEN_SANS_EXTRABOLD_11px_1bpp
+    if (fontId >= NANO_NB_FONTS) {
+      return 0;
+    } else {
+      return *((unsigned int *)(NANOX_FONTS_ARRAY_ADDR + (4 * fontId)));
+    }
   } else {
-    return *((unsigned int *)(STAX_FONTS_ARRAY_ADDR + (4 * fontId)));
+    return 0;
   }
 }
 
diff --git a/src/emulate_unified_sdk.c b/src/emulate_unified_sdk.c
index b63e00e0..4eca22c7 100644
--- a/src/emulate_unified_sdk.c
+++ b/src/emulate_unified_sdk.c
@@ -73,7 +73,7 @@ int emulate_syscall_nbgl(unsigned long syscall, unsigned long *parameters,
 {
   (void)version;
 
-  if (model != MODEL_STAX) {
+  if ((model != MODEL_STAX) && (version < SDK_API_LEVEL_15)) {
     return SYSCALL_NOT_HANDLED;
   }
 
diff --git a/src/fonts.h b/src/fonts.h
index b4e13f5b..18abba54 100644
--- a/src/fonts.h
+++ b/src/fonts.h
@@ -5,9 +5,16 @@
 // ============================================================================
 
 #define STAX_FONTS_ARRAY_ADDR 0x00805000
-#define STAX_NB_FONTS         7
+// Up to API_LEVEL_14, 7 fonts
+#define STAX_NB_FONTS_LEVEL_14 7
+// From API_LEVEL_15, 6 fonts
+#define STAX_NB_FONTS 6
 
-#define MAX_NB_FONTS STAX_NB_FONTS
+#define NANOSP_FONTS_ARRAY_ADDR 0x00805000
+#define NANOX_FONTS_ARRAY_ADDR  0x00205000
+#define NANO_NB_FONTS           3
+
+#define MAX_NB_FONTS STAX_NB_FONTS_LEVEL_14
 
 // ============================================================================
 // BAGL font related structures
diff --git a/src/launcher.c b/src/launcher.c
index 4c831f8d..bcb44f46 100644
--- a/src/launcher.c
+++ b/src/launcher.c
@@ -441,7 +441,18 @@ static int load_fonts(char *fonts_path)
 
   int flags = MAP_PRIVATE | MAP_FIXED;
   int prot = PROT_READ;
-  int load_addr = STAX_FONTS_ARRAY_ADDR;
+  int load_addr = 0;
+
+  if (hw_model == MODEL_STAX) {
+    load_addr = STAX_FONTS_ARRAY_ADDR;
+  } else if (hw_model == MODEL_NANO_SP) {
+    load_addr = NANOSP_FONTS_ARRAY_ADDR;
+  } else if (hw_model == MODEL_NANO_X) {
+    load_addr = NANOX_FONTS_ARRAY_ADDR;
+  } else {
+    warnx("hw_model %u not supported", hw_model);
+    return -1;
+  }
 
   void *p = mmap((void *)load_addr, load_size, prot, flags, fd, 0);
   fprintf(stderr, "[*] loaded fonts at %p\n", p);
@@ -769,7 +780,8 @@ int main(int argc, char *argv[])
   case MODEL_NANO_X:
     if (sdk_version != SDK_NANO_X_1_2 && sdk_version != SDK_NANO_X_2_0 &&
         sdk_version != SDK_NANO_X_2_0_2 && sdk_version != SDK_API_LEVEL_1 &&
-        sdk_version != SDK_API_LEVEL_5 && sdk_version != SDK_API_LEVEL_12) {
+        sdk_version != SDK_API_LEVEL_5 && sdk_version != SDK_API_LEVEL_12 &&
+        sdk_version != SDK_API_LEVEL_15) {
       errx(1, "invalid SDK version for the Ledger Nano X");
     }
     break;
@@ -781,7 +793,7 @@ int main(int argc, char *argv[])
   case MODEL_NANO_SP:
     if (sdk_version != SDK_NANO_SP_1_0 && sdk_version != SDK_NANO_SP_1_0_3 &&
         sdk_version != SDK_API_LEVEL_1 && sdk_version != SDK_API_LEVEL_5 &&
-        sdk_version != SDK_API_LEVEL_12) {
+        sdk_version != SDK_API_LEVEL_12 && sdk_version != SDK_API_LEVEL_15) {
       errx(1, "invalid SDK version for the Ledger NanoSP");
     }
     break;
@@ -791,7 +803,7 @@ int main(int argc, char *argv[])
         sdk_version != SDK_API_LEVEL_8 && sdk_version != SDK_API_LEVEL_9 &&
         sdk_version != SDK_API_LEVEL_10 && sdk_version != SDK_API_LEVEL_11 &&
         sdk_version != SDK_API_LEVEL_12 && sdk_version != SDK_API_LEVEL_13 &&
-        sdk_version != SDK_API_LEVEL_14) {
+        sdk_version != SDK_API_LEVEL_14 && sdk_version != SDK_API_LEVEL_15) {
       errx(1, "invalid SDK version for the Ledger Stax");
     }
     break;
@@ -818,7 +830,7 @@ int main(int argc, char *argv[])
 
   init_environment();
 
-  if (hw_model == MODEL_STAX && fonts_path) {
+  if (fonts_path) {
     if (load_fonts(fonts_path) != 0) {
       return 1;
     }
diff --git a/src/sdk.h b/src/sdk.h
index dd409b91..161f74a6 100644
--- a/src/sdk.h
+++ b/src/sdk.h
@@ -29,6 +29,7 @@ typedef enum {
   SDK_API_LEVEL_12,
   SDK_API_LEVEL_13,
   SDK_API_LEVEL_14,
+  SDK_API_LEVEL_15,
   SDK_COUNT
 } sdk_version_t;
 
diff --git a/tests/c/test_environment.c b/tests/c/test_environment.c
index 82c91a4a..4aa6dffa 100644
--- a/tests/c/test_environment.c
+++ b/tests/c/test_environment.c
@@ -60,12 +60,13 @@ static void check_is_default(field_e field)
     assert_memory_equal(&key[0], default_seed, MAX_SEED_SIZE);
     break;
   }
-  case FIELD_RNG:
+  case FIELD_RNG: {
     unsigned int now = time(NULL);
     // RNG is initialized in the past, not that long ago, but still
     // assert_int_equal(env_get_rng(), time(NULL)); can sometimes fail
     assert_in_range(env_get_rng(), now - 1, now);
     break;
+  }
   case FIELD_USER_KEY: {
     assert_memory_equal(env_get_user_private_key(1)->d,
                         default_user_private_key,