diff --git a/package.json b/package.json
index bcfaaa9..9a935a2 100644
--- a/package.json
+++ b/package.json
@@ -34,17 +34,17 @@
   },
   "homepage": "https://github.com/ipfs/js-datastore-core#readme",
   "devDependencies": {
-    "aegir": "^12.1.3",
+    "aegir": "^15.2.0",
     "chai": "^4.1.2",
     "dirty-chai": "^2.0.1",
-    "flow-bin": "^0.58.0"
+    "flow-bin": "~0.81.0"
   },
   "dependencies": {
-    "async": "^2.5.0",
-    "interface-datastore": "~0.4.0",
-    "left-pad": "^1.1.3",
+    "async": "^2.6.1",
+    "interface-datastore": "~0.5.0",
+    "left-pad": "^1.3.0",
     "pull-many": "^1.0.8",
-    "pull-stream": "^3.6.1"
+    "pull-stream": "^3.6.9"
   },
   "engines": {
     "node": ">=6.0.0",
diff --git a/src/mount.js b/src/mount.js
index 15e52c8..7c461d2 100644
--- a/src/mount.js
+++ b/src/mount.js
@@ -6,6 +6,7 @@ const many = require('pull-many')
 const pull = require('pull-stream')
 
 const Key = require('interface-datastore').Key
+const Errors = require('interface-datastore').Errors
 const utils = require('interface-datastore').utils
 const asyncFilter = utils.asyncFilter
 const asyncSort = utils.asyncSort
@@ -62,8 +63,9 @@ class MountDatastore /* :: <Value> */ {
   put (key /* : Key */, value /* : Value */, callback /* : Callback<void> */) /* : void */ {
     const match = this._lookup(key)
     if (match == null) {
-      callback(new Error('No datastore mounted for this key'))
-      return
+      return callback(
+        Errors.dbWriteFailedError(new Error('No datastore mounted for this key'))
+      )
     }
 
     match.datastore.put(match.rest, value, callback)
@@ -72,8 +74,9 @@ class MountDatastore /* :: <Value> */ {
   get (key /* : Key */, callback /* : Callback<Value> */) /* : void */ {
     const match = this._lookup(key)
     if (match == null) {
-      callback(new Error('No datastore mounted for this key'))
-      return
+      return callback(
+        Errors.notFoundError(new Error('No datastore mounted for this key'))
+      )
     }
 
     match.datastore.get(match.rest, callback)
@@ -92,8 +95,9 @@ class MountDatastore /* :: <Value> */ {
   delete (key /* : Key */, callback /* : Callback<void> */) /* : void */ {
     const match = this._lookup(key)
     if (match == null) {
-      callback(new Error('No datastore mounted for this key'))
-      return
+      return callback(
+        Errors.dbDeleteFailedError(new Error('No datastore mounted for this key'))
+      )
     }
 
     match.datastore.delete(match.rest, callback)
diff --git a/src/tiered.js b/src/tiered.js
index 35b2f6f..ddf93be 100644
--- a/src/tiered.js
+++ b/src/tiered.js
@@ -3,6 +3,7 @@
 
 const each = require('async/each')
 const whilst = require('async/whilst')
+const Errors = require('interface-datastore').Errors
 
 /* ::
 import type {Key, Datastore, Callback, Batch, Query, QueryResult} from 'interface-datastore'
@@ -25,13 +26,23 @@ class TieredDatastore /* :: <Value> */ {
   open (callback /* : Callback<void> */) /* : void */ {
     each(this.stores, (store, cb) => {
       store.open(cb)
-    }, callback)
+    }, (err) => {
+      if (err) {
+        return callback(Errors.dbOpenFailedError())
+      }
+      callback()
+    })
   }
 
   put (key /* : Key */, value /* : Value */, callback /* : Callback<void> */) /* : void */ {
     each(this.stores, (store, cb) => {
       store.put(key, value, cb)
-    }, callback)
+    }, (err) => {
+      if (err) {
+        return callback(Errors.dbWriteFailedError())
+      }
+      callback()
+    })
   }
 
   get (key /* : Key */, callback /* : Callback<Value> */) /* : void */ {
@@ -47,7 +58,12 @@ class TieredDatastore /* :: <Value> */ {
         }
         cb()
       })
-    }, callback)
+    }, (err, res) => {
+      if (err || !res) {
+        return callback(Errors.notFoundError())
+      }
+      callback(null, res)
+    })
   }
 
   has (key /* : Key */, callback /* : Callback<bool> */) /* : void */ {
@@ -69,7 +85,12 @@ class TieredDatastore /* :: <Value> */ {
   delete (key /* : Key */, callback /* : Callback<void> */) /* : void */ {
     each(this.stores, (store, cb) => {
       store.delete(key, cb)
-    }, callback)
+    }, (err) => {
+      if (err) {
+        return callback(Errors.dbDeleteFailedError())
+      }
+      callback()
+    })
   }
 
   close (callback /* : Callback<void> */) /* : void */ {