chore(python): deprecate uploading language blob during firmware update

diff --git a/python/.changelog.d/6103.removed b/python/.changelog.d/6103.removed
new file mode 100644
index 00000000..10a30829
--- /dev/null
+++ b/python/.changelog.d/6103.removed
@@ -0,0 +1 @@
+Deprecate uploading language blob during firmware update.
diff --git a/python/src/trezorlib/cli/firmware.py b/python/src/trezorlib/cli/firmware.py
index 1489a9df..a29649e6 100644
--- a/python/src/trezorlib/cli/firmware.py
+++ b/python/src/trezorlib/cli/firmware.py
@@ -17,7 +17,6 @@
 import os
 import sys
 import time
-from pathlib import Path
 from typing import (
     TYPE_CHECKING,
     Any,
@@ -614,7 +613,6 @@ def download(
 @click.option("-v", "--version", help="Which version to download")
 @click.option("-s", "--skip-check", is_flag=True, help="Do not validate firmware integrity")
 @click.option("-n", "--dry-run", is_flag=True, help="Perform all steps but do not actually upload the firmware")
-@click.option("-l", "--language", help="Language code, blob, or URL")
 @click.option("--bitcoin-only/--universal", is_flag=True, default=None, help="Download bitcoin-only or universal firmware (defaults to universal)")
 @click.option("--raw", is_flag=True, help="Push raw firmware data to Trezor")
 @click.option("--fingerprint", help="Expected firmware fingerprint in hex")
@@ -630,7 +628,6 @@ def update(
     raw: bool,
     dry_run: bool,
     bitcoin_only: Optional[bool],
-    language: Optional[str],
 ) -> None:
     """Upload new firmware to device.
 
@@ -649,23 +646,6 @@ def update(
             click.echo("You can use only one of: filename, url, version.")
             sys.exit(1)
 
-        language_data = b""
-        if language is not None:
-            if client.features.bootloader_mode:
-                click.echo("Language data cannot be uploaded in bootloader mode.")
-                sys.exit(1)
-
-            assert language is not None
-            try:
-                language_data = Path(language).read_bytes()
-            except Exception:
-                try:
-                    language_data = requests.get(language).content
-                except Exception:
-                    raise click.ClickException(
-                        f"Failed to load translations from {language}"
-                    ) from None
-
         if filename:
             firmware_data = filename.read()
         else:
@@ -703,13 +683,8 @@ def update(
                     seedless_session,
                     boot_command=messages.BootCommand.INSTALL_UPGRADE,
                     firmware_header=firmware_data[:header_size],
-                    language_data=language_data,
                 )
             else:
-                if language_data:
-                    click.echo(
-                        "WARNING: Seamless installation not possible, language data will not be uploaded."
-                    )
                 device.reboot_to_bootloader(seedless_session)
 
             click.echo("Waiting for bootloader...")
diff --git a/python/src/trezorlib/device.py b/python/src/trezorlib/device.py
index bdcf5427..779bd30e 100644
--- a/python/src/trezorlib/device.py
+++ b/python/src/trezorlib/device.py
@@ -605,18 +605,15 @@ def reboot_to_bootloader(
     session: "Session",
     boot_command: messages.BootCommand = messages.BootCommand.STOP_AND_WAIT,
     firmware_header: Optional[bytes] = None,
-    language_data: bytes = b"",
 ) -> str | None:
-    response = session.call(
+    ret = session.call(
         messages.RebootToBootloader(
             boot_command=boot_command,
             firmware_header=firmware_header,
-            language_data_length=len(language_data),
-        )
+        ),
+        expect=messages.Success,
     )
-    if isinstance(response, messages.DataChunkRequest):
-        response = _send_chunked_data(session, response, language_data)
-    return _return_success(messages.Success(message=""))
+    return _return_success(ret)
 
 
 def show_device_tutorial(session: "Session") -> str | None: