diff --git a/src/becca/becca.js b/src/becca/becca.js
index 8b1a3fcb9..4b08b7706 100644
--- a/src/becca/becca.js
+++ b/src/becca/becca.js
@@ -208,6 +208,7 @@ class Becca {
         return this.etapiTokens[etapiTokenId];
     }
 
+    /** @returns {AbstractBeccaEntity|null} */
     getEntity(entityName, entityId) {
         if (!entityName || !entityId) {
             return null;
diff --git a/src/becca/entities/abstract_becca_entity.js b/src/becca/entities/abstract_becca_entity.js
index cb539ef5d..9448ebb50 100644
--- a/src/becca/entities/abstract_becca_entity.js
+++ b/src/becca/entities/abstract_becca_entity.js
@@ -18,31 +18,11 @@ let becca = null;
 class AbstractBeccaEntity {
     /** @protected */
     beforeSaving() {
-        this.generateIdIfNecessary();
-    }
-
-    /** @protected */
-    generateIdIfNecessary() {
         if (!this[this.constructor.primaryKeyName]) {
             this[this.constructor.primaryKeyName] = utils.newEntityId();
         }
     }
 
-    /** @protected */
-    generateHash(isDeleted = false) {
-        let contentToHash = "";
-
-        for (const propertyName of this.constructor.hashedProperties) {
-            contentToHash += `|${this[propertyName]}`;
-        }
-
-        if (isDeleted) {
-            contentToHash += "|deleted";
-        }
-
-        return utils.hash(contentToHash).substr(0, 10);
-    }
-
     /** @protected */
     getUtcDateChanged() {
         return this.utcDateModified || this.utcDateCreated;
@@ -61,7 +41,7 @@ class AbstractBeccaEntity {
     }
 
     /** @protected */
-    putEntityChange(isDeleted = false) {
+    putEntityChange(isDeleted) {
         entityChangesService.putEntityChange({
             entityName: this.constructor.entityName,
             entityId: this[this.constructor.primaryKeyName],
@@ -72,11 +52,37 @@ class AbstractBeccaEntity {
         });
     }
 
+    /**
+     * @protected
+     * @returns {string}
+     */
+    generateHash(isDeleted) {
+        let contentToHash = "";
+
+        for (const propertyName of this.constructor.hashedProperties) {
+            contentToHash += `|${this[propertyName]}`;
+        }
+
+        if (isDeleted) {
+            contentToHash += "|deleted";
+        }
+
+        return utils.hash(contentToHash).substr(0, 10);
+    }
+
     /** @protected */
     getPojoToSave() {
         return this.getPojo();
     }
 
+    /**
+     * @protected
+     * @abstract
+     */
+    getPojo() {
+        throw new Error(`Unimplemented getPojo() for entity '${this.constructor.name}'`)
+    }
+
     /**
      * Saves entity - executes SQL, but doesn't commit the transaction on its own
      *
@@ -88,9 +94,7 @@ class AbstractBeccaEntity {
 
         const isNewEntity = !this[primaryKeyName];
 
-        if (this.beforeSaving) {
-            this.beforeSaving(opts);
-        }
+        this.beforeSaving(opts);
 
         const pojo = this.getPojoToSave();
 
@@ -101,7 +105,7 @@ class AbstractBeccaEntity {
                 return;
             }
 
-            this.putEntityChange(false);
+            this.putEntityChange(!!this.isDeleted);
 
             if (!cls.isEntityEventsDisabled()) {
                 const eventPayload = {
diff --git a/src/becca/entities/battachment.js b/src/becca/entities/battachment.js
index 7108545c7..2e1adfd0a 100644
--- a/src/becca/entities/battachment.js
+++ b/src/becca/entities/battachment.js
@@ -20,8 +20,7 @@ const attachmentRoleToNoteTypeMapping = {
 class BAttachment extends AbstractBeccaEntity {
     static get entityName() { return "attachments"; }
     static get primaryKeyName() { return "attachmentId"; }
-    static get hashedProperties() { return ["attachmentId", "ownerId", "role", "mime", "title", "blobId",
-                                            "utcDateScheduledForErasureSince", "utcDateModified"]; }
+    static get hashedProperties() { return ["attachmentId", "ownerId", "role", "mime", "title", "blobId", "utcDateScheduledForErasureSince"]; }
 
     constructor(row) {
         super();
diff --git a/src/services/entity_changes.js b/src/services/entity_changes.js
index c76f0fcd8..f1fd2eb5f 100644
--- a/src/services/entity_changes.js
+++ b/src/services/entity_changes.js
@@ -148,12 +148,13 @@ function fillEntityChanges(entityName, entityPrimaryKey, condition = '') {
                 const entity = becca.getEntity(entityName, entityId);
 
                 if (entity) {
-                    ec.hash = entity.generateHash() || "|deleted";
+                    ec.hash = entity.generateHash();
                     ec.utcDateChanged = entity.getUtcDateChanged() || dateUtils.utcNowDateTime();
                     ec.isSynced = entityName !== 'options' || !!entity.isSynced;
                 } else {
                     // entity might be null (not present in becca) when it's deleted
-                    // FIXME: hacky, not sure if it might cause some problems
+                    // this will produce different hash value than when entity is being deleted since then
+                    // all normal hashed attributes are being used. Sync should recover from that, though.
                     ec.hash = "deleted";
                     ec.utcDateChanged = dateUtils.utcNowDateTime();
                     ec.isSynced = true; // deletable (the ones with isDeleted) entities are synced
diff --git a/src/services/import/zip.js b/src/services/import/zip.js
index 15b50cd80..010a10346 100644
--- a/src/services/import/zip.js
+++ b/src/services/import/zip.js
@@ -456,7 +456,7 @@ async function importZip(taskContext, fileBuffer, importRootNote) {
                 position: attachmentMeta.position
             });
 
-            attachment.setContent(content);
+            attachment.setContent(content, { forceSave: true });
             return;
         }
 
diff --git a/src/services/sync_update.js b/src/services/sync_update.js
index aceb0d5be..919f3c8ce 100644
--- a/src/services/sync_update.js
+++ b/src/services/sync_update.js
@@ -106,7 +106,7 @@ function updateNormalEntity(remoteEC, remoteEntityRow, instanceId, updateContext
         updateContext.updated[remoteEC.entityName] = updateContext.updated[remoteEC.entityName] || [];
         updateContext.updated[remoteEC.entityName].push(remoteEC.entityId);
 
-        if (!localEC || localEC.utcDateChanged < remoteEC.utcDateChanged) {
+        if (!localEC || localEC.utcDateChanged < remoteEC.utcDateChanged || localEC.hash !== remoteEC.hash) {
             entityChangesService.putEntityChangeWithInstanceId(remoteEC, instanceId);
         }