I participated in a ICO using LTC however my Trezor has been converted to Segwit, now I would like to know if there is a way to sign this message.

The ICO support has told me to use this guide for blockchain.info:

https://github.com/OmniLayer/omniwallet/wiki/Exporting-Private-Key-from-Blockchain.info-and-Importing-to-Omniwallet.org

maybe I can download the LTC Core wallet and import the 24 word SEED & the segwit adress would show as Legacy adress?