There is no upgrade to use an 8V1090.00-1 with an ACP10 version 1.00 or greater, just as there is no possibility to use an 8V1090.00-2 with an ACP10 version less than 1.00. To put this in perspective, the -2 drives took over the -1 drives circa 2002-2004 (20+ years ago). The -1 drives are very old and are only supported by legacy software versions.
Very old versions are periodically removed from the website to keep the site from being bogged down with thousands of legacy downloads. As you have been pointed to by others, reaching out to your local B&R office is the best way to obtain these legacy downloads. The contact for technical support for Canadian customers is below.
CA - Canada (technical support for Canada is handled through the US)
Email: support.us@br-automation.com
Phone: +1 770-807-8737
Supported Language(s): English, French supported through local application team.