diff --git a/lib/read-only.js b/lib/read-only.js
index 15d6ea1..ed9e438 100644
--- a/lib/read-only.js
+++ b/lib/read-only.js
@@ -33,7 +33,7 @@ module.exports = Model => {
       const AffectedModel = Model.app.loopback.getModel(modelName)
       const options = AffectedModel.settings.mixins.ReadOnly
       const properties = (Object.keys(options).length) ? options : null
-      const instanceId = ctx.args[AffectedModel.getIdName()]
+      const instanceId = ctx.args[AffectedModel.getIdName()] || body.id
 
       if (properties) {
         debug('Found read only properties for model %s: %o', modelName, properties)
diff --git a/test/test.js b/test/test.js
index 2db2066..7956f39 100644
--- a/test/test.js
+++ b/test/test.js
@@ -153,7 +153,7 @@ describe('loopback datasource readonly property (mixin sources.js)', function()
           .send({ id: this.product.id, status: 'disabled' })
           .expect(200)
           .then(() => app.models.Product.findById(this.product.id))
-          .then(product => expect(product.status).to.equal('temp'))
+          .then(product => expect(product.status).to.equal('pending'))
       })
     })
 
@@ -186,7 +186,7 @@ describe('loopback datasource readonly property (mixin sources.js)', function()
           .send(Object.assign(this.product.toJSON(), { status: 'disabled' }))
           .expect(200)
           .then(() => app.models.Product.findById(this.product.id))
-          .then(product => expect(product.status).to.equal('temp'))
+          .then(product => expect(product.status).to.equal('pending'))
       })
     })