diff --git a/lib/Collaboration/Resources/ResourceProvider.php b/lib/Collaboration/Resources/ResourceProvider.php
index b4677148d..974976b0f 100644
--- a/lib/Collaboration/Resources/ResourceProvider.php
+++ b/lib/Collaboration/Resources/ResourceProvider.php
@@ -108,7 +108,7 @@ class ResourceProvider implements IProvider {
 
 	private function getBoard(IResource $resource) {
 		try {
-			return $this->boardMapper->find($resource->getId(), false, true);
+			return $this->boardMapper->find((int)$resource->getId(), false, true);
 		} catch (DoesNotExistException $e) {
 		} catch (MultipleObjectsReturnedException $e) {
 			return null;
diff --git a/lib/Db/BoardMapper.php b/lib/Db/BoardMapper.php
index 93be76d7e..5b1e6407e 100644
--- a/lib/Db/BoardMapper.php
+++ b/lib/Db/BoardMapper.php
@@ -79,12 +79,14 @@ class BoardMapper extends QBMapper implements IPermissionMapper {
 	 * @throws \OCP\AppFramework\Db\MultipleObjectsReturnedException
 	 * @throws DoesNotExistException
 	 */
-	public function find($id, $withLabels = false, $withAcl = false): Board {
+	public function find(int $id, bool $withLabels = false, bool $withAcl = false, bool $allowDeleted = false): Board {
 		if (!isset($this->boardCache[$id])) {
 			$qb = $this->db->getQueryBuilder();
+			$deletedWhere = $allowDeleted ? $qb->expr()->gte('deleted_at', $qb->createNamedParameter(0, IQueryBuilder::PARAM_INT)) : $qb->expr()->eq('deleted_at', $qb->createNamedParameter(0, IQueryBuilder::PARAM_INT));
 			$qb->select('*')
 				->from('deck_boards')
 				->where($qb->expr()->eq('id', $qb->createNamedParameter($id, IQueryBuilder::PARAM_INT)))
+				->andWhere($deletedWhere)
 				->orderBy('id');
 			$this->boardCache[$id] = $this->findEntity($qb);
 		}
diff --git a/lib/Service/BoardService.php b/lib/Service/BoardService.php
index 9a98decbf..2c3bca46b 100644
--- a/lib/Service/BoardService.php
+++ b/lib/Service/BoardService.php
@@ -181,7 +181,7 @@ class BoardService {
 	 * @throws \OCP\AppFramework\Db\MultipleObjectsReturnedException
 	 * @throws BadRequestException
 	 */
-	public function find($boardId) {
+	public function find($boardId, bool $allowDeleted = false) {
 		$this->boardServiceValidator->check(compact('boardId'));
 		if ($this->boardsCache && isset($this->boardsCache[$boardId])) {
 			return $this->boardsCache[$boardId];
@@ -192,7 +192,7 @@ class BoardService {
 
 		$this->permissionService->checkPermission($this->boardMapper, $boardId, Acl::PERMISSION_READ);
 		/** @var Board $board */
-		$board = $this->boardMapper->find($boardId, true, true);
+		$board = $this->boardMapper->find($boardId, true, true, $allowDeleted);
 		$this->boardMapper->mapOwner($board);
 		if ($board->getAcl() !== null) {
 			foreach ($board->getAcl() as $acl) {
@@ -367,7 +367,7 @@ class BoardService {
 		$this->boardServiceValidator->check(compact('id'));
 
 		$this->permissionService->checkPermission($this->boardMapper, $id, Acl::PERMISSION_MANAGE);
-		$board = $this->find($id);
+		$board = $this->find($id, true);
 		$board->setDeletedAt(0);
 		$board = $this->boardMapper->update($board);
 		$this->activityManager->triggerEvent(ActivityManager::DECK_OBJECT_BOARD, $board, ActivityManager::SUBJECT_BOARD_RESTORE);
@@ -388,7 +388,7 @@ class BoardService {
 		$this->boardServiceValidator->check(compact('id'));
 
 		$this->permissionService->checkPermission($this->boardMapper, $id, Acl::PERMISSION_MANAGE);
-		$board = $this->find($id);
+		$board = $this->find($id, true);
 		$delete = $this->boardMapper->delete($board);
 
 		return $delete;
diff --git a/lib/Service/CardService.php b/lib/Service/CardService.php
index 8d8522790..c648e0979 100644
--- a/lib/Service/CardService.php
+++ b/lib/Service/CardService.php
@@ -274,6 +274,14 @@ class CardService {
 		if ($archived !== null && $card->getArchived() && $archived === true) {
 			throw new StatusException('Operation not allowed. This card is archived.');
 		}
+
+		if ($card->getDeletedAt() !== 0) {
+			if ($deletedAt === null) {
+				// Only allow operations when restoring the card
+				throw new StatusException('Operation not allowed. This card was deleted.');
+			}
+		}
+
 		$changes = new ChangeSet($card);
 		if ($card->getLastEditor() !== $this->currentUser && $card->getLastEditor() !== null) {
 			$this->activityManager->triggerEvent(
diff --git a/lib/Service/PermissionService.php b/lib/Service/PermissionService.php
index 06a6da62d..c42ca8045 100644
--- a/lib/Service/PermissionService.php
+++ b/lib/Service/PermissionService.php
@@ -194,11 +194,11 @@ class PermissionService {
 	 * @throws MultipleObjectsReturnedException
 	 * @throws DoesNotExistException
 	 */
-	private function getBoard($boardId): Board {
-		if (!isset($this->boardCache[$boardId])) {
-			$this->boardCache[$boardId] = $this->boardMapper->find($boardId, false, true);
+	private function getBoard(int $boardId): Board {
+		if (!isset($this->boardCache[(string)$boardId])) {
+			$this->boardCache[(string)$boardId] = $this->boardMapper->find($boardId, false, true);
 		}
-		return $this->boardCache[$boardId];
+		return $this->boardCache[(string)$boardId];
 	}
 
 	/**
diff --git a/tests/unit/Activity/ActivityManagerTest.php b/tests/unit/Activity/ActivityManagerTest.php
index d292d9023..f7b011c05 100644
--- a/tests/unit/Activity/ActivityManagerTest.php
+++ b/tests/unit/Activity/ActivityManagerTest.php
@@ -124,6 +124,7 @@ class ActivityManagerTest extends TestCase {
 
 	public function testCreateEvent() {
 		$board = new Board();
+		$board->setId(123);
 		$board->setTitle('');
 		$this->boardMapper->expects($this->once())
 			->method('find')