OAuth consent screen - ability to remove application logo

Solution 1:

In order to delete the logo, follow these steps:

• Open the OAuth Consent Screen Configuration in Chrome or a Chromium derivative. https://console.cloud.google.com/apis/credentials/consent
• Upload any image that differs from the one previously uploaded.
• Open your Developer Tools (F12 or Ctrl+Shift+I).
• Open the Network tab.
• (Optional) Press the Clear button to make it easier to search later.
• Click the Save button on the website to upload the new logo. (If the Save button is disabled, go through the full "Submit for Verification" process.)
• In the Network tab, look for a request similar to "123456789987?alt=json&key=...".
• Click on the entry and ensure that the Request Method is PUT.
• Right-Click the entry and select "Copy"->"Copy as cURL (bash)".
• Paste it into a text editor and search for the text "iconUrl":"https://...".
• Change the text to read like the following: "iconUrl":"".
• Back on the site, open up a Cloud Console session (The terminal icon in the top menu bar) and paste the modified command, then run it.
• Verify that logo got removed from consent screen and verification status has changed.

Please keep in mind that this may require you to verify your app again.

Since June 11th of 2020 there's a Feature request open requesting the adition of a remove logo button to make this process easier. Please leave your comment, star the issue and leave a +1 if you are also affected by this issue.

Solution 2:

As of May 31, 2021 (EDIT: mcriecken confirmed this worked as of Dec 2021) I was able to remove the icon with following steps. Since this is a combination of two answers above with additional steps I put all the steps here for clarity. Credits to @Chris32 and @ropsnou for the initial steps.

1. Remove all existing API keys and Client IDs from the OAuth Credentials page
2. Open the OAuth Consent Screen Configuration in Chrome or a Chromium derivative.
3. Upload any image that differs from the one previously uploaded and click "Save and continue"
4. In the Network tab, look for a PUT request like this: https://clientauthconfig.clients6.google.com/v1/brands/745625634622/icon?key={key}
5. Right-Click the request and select "Copy"->"Copy as cURL (bash)".
6. Paste it into a text editor and do following changes
   • Remove /icon from the url
   • Change request method to DELETE
   • Remove --data-raw parameter and its long value
7. Activate Cloud Shell by clicking the terminal icon in the top-right corner of the GCP website. Paste and run the command you modified in the previous step. If you get INVALID_ARGUMENT error you probably still have an API key or Client ID associated with the consent screen. If you get {} the command was successful and the logo was removed. However, together with the logo a larger brand entity was also removed, and if you try to modify the consent screen you will get "An error saving your app has occurred."
8. To recreate the brand run the following command in the Cloud Shell (it assumes you have the correct project active):
   EDIT: The command may fail for two reasons (see comments for more info):
   • User is not owner of the email
   • Project is not in an organization

gcloud alpha iap oauth-brands create --application_title='<title>' --support_email='<email>'

9. Now the logo is gone and you can again modify the consent screen

Solution 3:

For those who were unable to update it using the 'PUT' method (as answered by @Chris32 )and are ready to delete the consent screen and create a new one, can simply replace 'PUT' with 'DELETE' and remove --data-binary section (as delete doesn't take any payload) and can run it using a regular bash shell.