diff --git a/viewer/download_structures.py b/viewer/download_structures.py
index c5191f29..4382491e 100644
--- a/viewer/download_structures.py
+++ b/viewer/download_structures.py
@@ -35,7 +35,7 @@
     'bound_file': ('aligned'),
     'cif_info': ('aligned'),
     'mtz_info': ('aligned'),
-    # 'map_info': ('aligned'),
+    'map_info': ('aligned'),
     'sigmaa_file': ('aligned'),
     'diff_file': ('aligned'),
     'event_file': ('aligned'),
@@ -56,8 +56,9 @@
         'bound_file': {},  # x
         'cif_info': {},  # from experiment
         'mtz_info': {},  # from experiment
+        'map_info': {},  # from experiment
         'event_file': {},  # x
-        'diff_file': {},  # renamed from diff_file and sigmaa_file
+        'diff_file': {},
         'sigmaa_file': {},
     },
     'molecules': {
@@ -229,6 +230,7 @@ def _add_file_to_zip_aligned(ziparchive, code, filepath):
         filepath = str(Path(settings.MEDIA_ROOT).joinpath(filepath))
 
     if Path(filepath).is_file():
+        # strip off the leading parts of path
         archive_path = str(Path(*Path(filepath).parts[7:]))
         if _is_mol_or_sdf(filepath):
             # It's a MOL or SD file.
@@ -285,9 +287,13 @@ def _protein_files_zip(zip_contents, ziparchive, error_file):
             continue
 
         for prot, prot_file in files.items():
-            if not _add_file_to_zip_aligned(ziparchive, prot.split(":")[0], prot_file):
-                error_file.write(f'{param},{prot},{prot_file}\n')
-                prot_errors += 1
+            # if it's a list of files (map_info) instead of single file
+            if not isinstance(prot_file, list):
+                prot_file = [prot_file]
+            for f in prot_file:
+                if not _add_file_to_zip_aligned(ziparchive, prot.split(":")[0], f):
+                    error_file.write(f'{param},{prot},{f}\n')
+                    prot_errors += 1
 
     return prot_errors
 
@@ -606,10 +612,14 @@ def _create_structures_dict(target, site_obvs, protein_params, other_params):
                     # getting the param from experiment. more data are
                     # coming from there, that's why this is in try
                     # block
-                    # getattr retrieves FieldFile object, hance the .name
-                    zip_contents['proteins'][param][so.code] = getattr(
-                        so.experiment, param
-                    ).name
+                    model_attr = getattr(so.experiment, param)
+                    # getattr retrieves FieldFile object, hence the .name
+                    if isinstance(model_attr, list):
+                        # except map_files, this returns a list of files
+                        zip_contents['proteins'][param][so.code] = model_attr
+                    else:
+                        zip_contents['proteins'][param][so.code] = model_attr.name
+
                 except AttributeError:
                     # on the off chance that the data are in site_observation model
                     zip_contents['proteins'][param][so.code] = getattr(so, param).name
@@ -686,6 +696,7 @@ def get_download_params(request):
         'bound_file',
         'cif_info',
         'mtz_info',
+        'map_info',
         'event_file',
         'sigmaa_file',
         'diff_file',
diff --git a/viewer/migrations/0034_experiment_map_info.py b/viewer/migrations/0034_experiment_map_info.py
new file mode 100644
index 00000000..333c6988
--- /dev/null
+++ b/viewer/migrations/0034_experiment_map_info.py
@@ -0,0 +1,19 @@
+# Generated by Django 3.2.23 on 2024-01-26 11:16
+
+from django.db import migrations, models
+
+
+class Migration(migrations.Migration):
+    dependencies = [
+        ('viewer', '0033_alter_siteobservation_cmpd'),
+    ]
+
+    operations = [
+        migrations.AddField(
+            model_name='experiment',
+            name='map_info',
+            field=models.FileField(
+                max_length=255, null=True, upload_to='target_loader_data/'
+            ),
+        ),
+    ]
diff --git a/viewer/migrations/0035_alter_experiment_event_map_info.py b/viewer/migrations/0035_alter_experiment_event_map_info.py
new file mode 100644
index 00000000..cca1fd89
--- /dev/null
+++ b/viewer/migrations/0035_alter_experiment_event_map_info.py
@@ -0,0 +1,22 @@
+# Generated by Django 3.2.23 on 2024-01-30 08:09
+
+import django.contrib.postgres.fields
+from django.db import migrations, models
+
+
+class Migration(migrations.Migration):
+    dependencies = [
+        ('viewer', '0034_experiment_map_info'),
+    ]
+
+    operations = [
+        migrations.AlterField(
+            model_name='experiment',
+            name='event_map_info',
+            field=django.contrib.postgres.fields.ArrayField(
+                base_field=models.FileField(max_length=255, upload_to=''),
+                null=True,
+                size=None,
+            ),
+        ),
+    ]
diff --git a/viewer/migrations/0036_remove_experiment_map_info.py b/viewer/migrations/0036_remove_experiment_map_info.py
new file mode 100644
index 00000000..5fd950ac
--- /dev/null
+++ b/viewer/migrations/0036_remove_experiment_map_info.py
@@ -0,0 +1,16 @@
+# Generated by Django 3.2.23 on 2024-01-30 08:12
+
+from django.db import migrations
+
+
+class Migration(migrations.Migration):
+    dependencies = [
+        ('viewer', '0035_alter_experiment_event_map_info'),
+    ]
+
+    operations = [
+        migrations.RemoveField(
+            model_name='experiment',
+            name='map_info',
+        ),
+    ]
diff --git a/viewer/migrations/0037_rename_event_map_info_experiment_map_info.py b/viewer/migrations/0037_rename_event_map_info_experiment_map_info.py
new file mode 100644
index 00000000..049a3383
--- /dev/null
+++ b/viewer/migrations/0037_rename_event_map_info_experiment_map_info.py
@@ -0,0 +1,17 @@
+# Generated by Django 3.2.23 on 2024-01-30 08:12
+
+from django.db import migrations
+
+
+class Migration(migrations.Migration):
+    dependencies = [
+        ('viewer', '0036_remove_experiment_map_info'),
+    ]
+
+    operations = [
+        migrations.RenameField(
+            model_name='experiment',
+            old_name='event_map_info',
+            new_name='map_info',
+        ),
+    ]
diff --git a/viewer/models.py b/viewer/models.py
index 62b44044..0feb65d3 100644
--- a/viewer/models.py
+++ b/viewer/models.py
@@ -193,7 +193,7 @@ class Experiment(models.Model):
     cif_info = models.FileField(
         upload_to="target_loader_data/", null=True, max_length=255
     )
-    event_map_info = ArrayField(models.FileField(), null=True)
+    map_info = ArrayField(models.FileField(max_length=255), null=True)
     type = models.PositiveSmallIntegerField(null=True)
     pdb_sha256 = models.TextField(null=True)
     compounds = models.ManyToManyField(
diff --git a/viewer/serializers.py b/viewer/serializers.py
index 807d6ffb..7ae642cc 100644
--- a/viewer/serializers.py
+++ b/viewer/serializers.py
@@ -832,6 +832,7 @@ class DownloadStructuresSerializer(serializers.Serializer):
     diff_file = serializers.BooleanField(default=False)
     event_file = serializers.BooleanField(default=False)
     sigmaa_file = serializers.BooleanField(default=False)
+    map_info = serializers.BooleanField(default=False)
     sdf_info = serializers.BooleanField(default=False)
     single_sdf_file = serializers.BooleanField(default=False)
     metadata_info = serializers.BooleanField(default=False)
diff --git a/viewer/target_loader.py b/viewer/target_loader.py
index 28286930..f9656edf 100644
--- a/viewer/target_loader.py
+++ b/viewer/target_loader.py
@@ -5,11 +5,12 @@
 import os
 import tarfile
 import uuid
+from collections.abc import Callable
 from dataclasses import dataclass, field
 from enum import Enum
 from pathlib import Path
 from tempfile import TemporaryDirectory
-from typing import Any, Dict, Iterable, List, Optional, TypeVar
+from typing import Any, Dict, Iterable, List, Optional, Tuple, TypeVar
 
 import yaml
 from celery import Task
@@ -45,7 +46,7 @@
 
 # data that goes to tables are in the following files
 # assemblies and xtalforms
-XTALFORMS_FILE = "crystalforms.yaml"
+XTALFORMS_FILE = "assemblies.yaml"
 
 # target name, nothing else
 CONFIG_FILE = "config*.yaml"
@@ -313,12 +314,20 @@ def wrapper_create_objects(
 
             obj = None
             try:
-                obj, new = instance_data.model_class.filter_manager.by_target(
-                    self.target
-                ).get_or_create(
-                    **instance_data.fields,
-                    defaults=instance_data.defaults,
-                )
+                if instance_data.fields:
+                    obj, new = instance_data.model_class.filter_manager.by_target(
+                        self.target
+                    ).get_or_create(
+                        **instance_data.fields,
+                        defaults=instance_data.defaults,
+                    )
+                else:
+                    # no unique field requirements, just create new object
+                    obj = instance_data.model_class(
+                        **instance_data.defaults,
+                    )
+                    obj.save()
+                    new = True
                 logger.debug(
                     "%s object %s created",
                     instance_data.model_class._meta.object_name,  # pylint: disable=protected-access
@@ -329,8 +338,9 @@ def wrapper_create_objects(
                 else:
                     existing = existing + 1
             except MultipleObjectsReturned:
-                msg = "{}.get_or_create returned multiple objects for {}".format(
+                msg = "{}.get_or_create in {} returned multiple objects for {}".format(
                     instance_data.model_class._meta.object_name,  # pylint: disable=protected-access
+                    instance_data.key,
                     instance_data.fields,
                 )
                 self.report.log(Level.FATAL, msg)
@@ -457,6 +467,32 @@ def final_path(self) -> Path:
     def abs_final_path(self) -> Path:
         return self._abs_final_path
 
+    def validate_map_files(
+        self,
+        key: str,
+        obj_identifier: str,
+        file_struct: list,
+    ) -> list[str]:
+        """Validate list of panddas event files.
+
+        Special case of file validation, too complex to squeeze into
+        the main validation method (mainly because of typing).
+        """
+
+        def logfunc(_, message):
+            self.report.log(Level.WARNING, message)
+
+        result = []
+        for item in file_struct:
+            fname, file_hash = self._check_file(item, obj_identifier, key, logfunc)
+            if not fname:
+                continue
+
+            self._check_file_hash(obj_identifier, key, fname, file_hash, logfunc)
+            result.append(fname)
+
+        return result
+
     def validate_files(
         self,
         obj_identifier: str,
@@ -509,48 +545,26 @@ def logfunc(key, message):
 
             # sort out the filename
             if isinstance(value, dict):
-                file_hash = value.get("sha256", None)
-                try:
-                    filename = value["file"]
-                except KeyError:
-                    # this is rather unexpected, haven't seen it yet
-                    logfunc(
-                        key,
-                        "{}: malformed dict, key 'file' missing".format(obj_identifier),
-                    )
-
-                    # unable to extract file from dict, no point to
-                    # continue with hash checking
+                filename, file_hash = self._check_file(
+                    value, obj_identifier, key, logfunc
+                )
+                if not filename:
                     continue
 
+                self._check_file_hash(obj_identifier, key, filename, file_hash, logfunc)
+
             elif isinstance(value, str):
                 filename = value
+                self._check_file_hash(obj_identifier, key, filename, file_hash, logfunc)
+
             else:
-                # this is probably the list of panddas event files, don't
-                # need them here
-                # although.. should i validate them here nevertheless?
-                # i'd have to do this on copy otherwise..
+                # probably panddas files here
                 continue
 
             # file key should go to result dict no matter what
             result[key] = filename
             logger.debug("Adding key %s: %s", key, filename)
 
-            # filename resolved, check if exists and if given, hash
-            file_path = self.raw_data.joinpath(filename)
-            if file_path.is_file():
-                if file_hash and file_hash != calculate_sha256(file_path):
-                    logfunc(key, "Invalid hash for file {}".format(filename))
-            else:
-                logfunc(
-                    key,
-                    "{} referenced in {}: {} but not found in archive".format(
-                        key,
-                        METADATA_FILE,
-                        obj_identifier,
-                    ),
-                )
-
         files = []
         for f in list(required) + list(recommended):
             try:
@@ -564,11 +578,59 @@ def logfunc(key, message):
                         METADATA_FILE,
                     ),
                 )
-                files.append(None)
+                files.append(None)  # type: ignore [arg-type]
 
         logger.debug("Returning files: %s", files)
 
-        return files
+        # memo to self: added type ignore directives to return line
+        # below and append line above because after small refactoring,
+        # mypy all of the sudden started throwing errors on bothe or
+        # these. the core of it's grievance is that it expects the
+        # return type to be list[str]. no idea why, function signature
+        # clearly defines it as list[str | None]
+
+        return files  # type: ignore [return-value]
+
+    def _check_file(
+        self,
+        value: dict,
+        obj_identifier: str,
+        key: str,
+        logfunc: Callable,
+    ) -> Tuple[str | None, str | None]:
+        file_hash = value.get("sha256", None)
+        try:
+            filename = value["file"]
+        except KeyError:
+            # this is rather unexpected, haven't seen it yet
+            filename = None
+            logfunc(
+                key,
+                "{}: malformed dict, key 'file' missing".format(obj_identifier),
+            )
+        return filename, file_hash
+
+    def _check_file_hash(
+        self,
+        obj_identifier: str,
+        key: str,
+        filename: str,
+        file_hash: str | None,
+        logfunc: Callable,
+    ) -> None:
+        file_path = self.raw_data.joinpath(filename)
+        if file_path.is_file():
+            if file_hash and file_hash != calculate_sha256(file_path):
+                logfunc(key, "Invalid hash for file {}".format(filename))
+        else:
+            logfunc(
+                key,
+                "{} referenced in {}: {} but not found in archive".format(
+                    key,
+                    METADATA_FILE,
+                    obj_identifier,
+                ),
+            )
 
     @create_objects(depth=1)
     def process_experiment(
@@ -589,9 +651,15 @@ def process_experiment(
                     'xtal_mtz': {
                         'file': 'upload_1/crystallographic_files/5rgs/5rgs.mtz',
                         'sha256': sha <str>,
-                    }
-                },
+                    },
+                    'panddas_event_files': {
+                        'file': <path>.ccp4,
+                        'sha256': sha <str>,
+                        'model': '1', chain: B, res: 203, index: 1, bdc: 0.23
+                    },
                 'status': 'new',
+                },
+
             }
         )
 
@@ -619,13 +687,24 @@ def process_experiment(
         ) = self.validate_files(
             obj_identifier=experiment_name,
             file_struct=data["crystallographic_files"],
-            required=("xtal_pdb",),
             recommended=(
+                "xtal_pdb",
                 "xtal_mtz",
                 "ligand_cif",
             ),
         )
 
+        try:
+            panddas_files = data["crystallographic_files"]["panddas_event_files"]
+        except KeyError:
+            panddas_files = []
+
+        map_info_files = self.validate_map_files(
+            key="panddas_event_files",
+            obj_identifier=experiment_name,
+            file_struct=panddas_files,
+        )
+
         dtype = extract(key="type")
 
         if dtype == "manual":
@@ -640,13 +719,16 @@ def process_experiment(
 
         dstatus = extract(key="status")
 
-        if dstatus == "new":
-            status = 0
-        elif dstatus == "deprecated":
-            status = 1
-        elif dstatus == "superseded":
-            status = 2
-        else:
+        status_codes = {
+            "new": 0,
+            "deprecated": 1,
+            "superseded": 2,
+            "unchanged": 3,
+        }
+
+        try:
+            status = status_codes[dstatus]
+        except KeyError:
             status = -1
             self.report.log(
                 Level.FATAL, f"Unexpected status '{dstatus}' for {experiment_name}"
@@ -660,6 +742,11 @@ def process_experiment(
             "experiment_upload": self.experiment_upload,
             "code": experiment_name,
         }
+
+        map_info_paths = []
+        if map_info_files:
+            map_info_paths = [str(self._get_final_path(k)) for k in map_info_files]
+
         defaults = {
             "status": status,
             "version": version,
@@ -667,6 +754,7 @@ def process_experiment(
             "pdb_info": str(self._get_final_path(pdb_info)),
             "mtz_info": str(self._get_final_path(mtz_info)),
             "cif_info": str(self._get_final_path(cif_info)),
+            "map_info": map_info_paths,
             # this doesn't seem to be present
             # pdb_sha256:
         }
@@ -730,14 +818,14 @@ def process_compound(
             )
             return None
 
-        fields = {
+        defaults = {
             "smiles": smiles,
+            "compound_code": data.get("compound_code", None),
         }
-        defaults = {"compound_code": data.get("compound_code", None)}
 
         return ProcessedObject(
             model_class=Compound,
-            fields=fields,
+            fields={},
             defaults=defaults,
             key=protein_name,
         )
@@ -1037,11 +1125,16 @@ def process_xtalform_site(
             "residues": residues,
         }
 
+        index_data = {
+            "residues": residues,
+        }
+
         return ProcessedObject(
             model_class=XtalformSite,
             fields=fields,
             defaults=defaults,
             key=xtalform_site_name,
+            index_data=index_data,
         )
 
     @create_objects(depth=5)
@@ -1132,6 +1225,7 @@ def process_site_observation(
             ),
         )
 
+        logger.debug('looking for ligand_mol: %s', ligand_mol)
         mol_data = None
         if ligand_mol:
             try:
@@ -1141,7 +1235,7 @@ def process_site_observation(
                     encoding="utf-8",
                 ) as f:
                     mol_data = f.read()
-            except TypeError:
+            except (TypeError, FileNotFoundError):
                 # this site observation doesn't have a ligand. perfectly
                 # legitimate case
                 pass
@@ -1413,7 +1507,7 @@ def process_bundle(self):
         # key for xtal sites objects?
         xtalform_site_by_tag = {}
         for val in xtalform_sites_objects.values():  # pylint: disable=no-member
-            for k in val.instance.residues:
+            for k in val.index_data["residues"]:
                 xtalform_site_by_tag[k] = val.instance
 
         site_observation_objects = self.process_site_observation(