From 4a88d1b823c66a9a83da10ed9163df2a1b8bfb4a Mon Sep 17 00:00:00 2001
From: Eric Larson <larson.eric.d@gmail.com>
Date: Tue, 11 Feb 2025 13:48:28 -0500
Subject: [PATCH 1/3] BUG: Fix dev_head_t for EEG data

---
 mne/_fiff/meas_info.py       | 8 ++++++--
 mne/io/egi/egimff.py         | 2 +-
 mne/io/egi/tests/test_egi.py | 1 +
 3 files changed, 8 insertions(+), 3 deletions(-)

diff --git a/mne/_fiff/meas_info.py b/mne/_fiff/meas_info.py
index 28f0629c323..8eac4b2bf1e 100644
--- a/mne/_fiff/meas_info.py
+++ b/mne/_fiff/meas_info.py
@@ -3315,7 +3315,7 @@ def create_info(ch_names, sfreq, ch_types="misc", verbose=None):
 )
 
 
-def _empty_info(sfreq):
+def _empty_info(sfreq, *, dev_head_t=True):
     """Create an empty info dictionary."""
     from ..transforms import Transform
 
@@ -3364,7 +3364,11 @@ def _empty_info(sfreq):
     info["highpass"] = 0.0
     info["sfreq"] = float(sfreq)
     info["lowpass"] = info["sfreq"] / 2.0
-    info["dev_head_t"] = Transform("meg", "head")
+    if dev_head_t is True:
+        dev_head_t = Transform("meg", "head")
+    elif dev_head_t is False:
+        dev_head_t = None
+    info["dev_head_t"] = dev_head_t
     info._update_redundant()
     info._check_consistency()
     return info
diff --git a/mne/io/egi/egimff.py b/mne/io/egi/egimff.py
index c3a10fb72cd..c68723c23d5 100644
--- a/mne/io/egi/egimff.py
+++ b/mne/io/egi/egimff.py
@@ -440,7 +440,7 @@ def __init__(
         assert egi_events.shape[1] == egi_info["last_samps"][-1]
 
         meas_dt_utc = egi_info["meas_dt_local"].astimezone(datetime.timezone.utc)
-        info = _empty_info(egi_info["sfreq"])
+        info = _empty_info(egi_info["sfreq"], dev_head_t=False)
         info["meas_date"] = _ensure_meas_date_none_or_dt(meas_dt_utc)
         info["utc_offset"] = egi_info["utc_offset"]
         info["device_info"] = dict(type=egi_info["device"])
diff --git a/mne/io/egi/tests/test_egi.py b/mne/io/egi/tests/test_egi.py
index 584714d9c8a..08995fba6a0 100644
--- a/mne/io/egi/tests/test_egi.py
+++ b/mne/io/egi/tests/test_egi.py
@@ -83,6 +83,7 @@ def test_egi_mff_pause(fname, skip_times, event_times):
                 events_as_annotations=False,
             )
     assert raw.info["sfreq"] == 250.0  # true for all of these files
+    assert raw.info["dev_head_t"] is None  # no MEG data
     assert len(raw.annotations) == len(skip_times)
 
     # assert event onsets match expected times

From c8a0cb188d8160e14f85dc86e15b0333eca26bc4 Mon Sep 17 00:00:00 2001
From: Eric Larson <larson.eric.d@gmail.com>
Date: Tue, 11 Feb 2025 14:05:26 -0500
Subject: [PATCH 2/3] FIX: CL

---
 doc/changes/devel/bugfix.rst | 1 +
 1 file changed, 1 insertion(+)
 create mode 100644 doc/changes/devel/bugfix.rst

diff --git a/doc/changes/devel/bugfix.rst b/doc/changes/devel/bugfix.rst
new file mode 100644
index 00000000000..1bffca6cdef
--- /dev/null
+++ b/doc/changes/devel/bugfix.rst
@@ -0,0 +1 @@
+Fix bug with :func:`mne.io.read_raw_egi` where ``info["dev_head_t"]`` was an identity matrix instead of ``None``, by `Eric Larson`_.

From b13f7c32808d448db48e5a51b8c4fed1a41c3ac1 Mon Sep 17 00:00:00 2001
From: "autofix-ci[bot]" <114827586+autofix-ci[bot]@users.noreply.github.com>
Date: Tue, 11 Feb 2025 19:06:01 +0000
Subject: [PATCH 3/3] [autofix.ci] apply automated fixes

---
 doc/changes/devel/{bugfix.rst => 13112.bugfix.rst} | 0
 1 file changed, 0 insertions(+), 0 deletions(-)
 rename doc/changes/devel/{bugfix.rst => 13112.bugfix.rst} (100%)

diff --git a/doc/changes/devel/bugfix.rst b/doc/changes/devel/13112.bugfix.rst
similarity index 100%
rename from doc/changes/devel/bugfix.rst
rename to doc/changes/devel/13112.bugfix.rst