- copy the install*.chrdownload file (i.e. the temporary file into which the file was being downloaded) into some other folder
- cancel the download
- start a fresh download
- pause it
- overwrite the new .chrdowload file with the old one
However, this trick did not work with Chrome. It was still downloading more than 100 mb as if it were the fresh download.
I opened up Firefox and applied the same procedure except for renaming the .chrdownload file to .part file and Firefox intelligently downloaded only what remained of the file completing the download in minutes.