Convert Bootable USB to an ISO Image

Download and install ImgBurn from this link; (make sure you don’t install any other software packaged with it)

http://www.imgburn.com/

Insert your USB drive into the computer and start ImgBurn program. Click “Create Image File From Files/Folders”;

Click “Browse” button right next to the Source option on top-left corner and select the USB drive. In the “Destination” option right under it, click the “Browse” button and select the destination folder and enter the file name. When done, click the “Advanced” tab on the right and then click the “Bootable Disc” tab under it;

Enable the check-box labeled as “Make Image Bootable” and click the “Browse” option next to the “Boot Image” and select “etfsboot.com” file in the “Boot” folder on the USB drive. Enter “Microsoft Corporation” in the “Developer ID” box. Make sure that “Load Segment” box is labeled as “07C0” (where 0 is zero, not “O”). Enter 8 in the “Sectors to Load” (if you are building Windows 7 or Windows 10 image). In case of Windows Vista, enter 4.

Next, under the Advanced –> Restrictions –> ISO9660, checkmark the box labeled “Allow Files Exceeding Size Limit” (Single Extent);

When done, click “Build” button marked as a folder to CD on bottom to continue;

In the next dialog box “Confirm Volume Label”, accept the default values and press “Yes” to continue;

In the pop-up box with final values, Click “OK” to start building the ISO image file process;

When done building the ISO image, it will show you the dialog box as below;

Updated: 25 Jan 2020

Credits: AdyGudus from https://forums.hak5.org/index.php?/topic/15567-convert-bootable-usb-to-iso/