as an exercise we need to reverse a sha1 to get the 'original' message.

All we know is that the lowercase sha1 of the code gives: B39ECFBC2C64ADBB7C7A9292EEE31794D28FE224

And the sha1 of the case sensitive code should be: 0D353038908AD0FC8C51A5312BB3E2FEE1CDDF83

And the broken original message: HV15-G.UJ-1.Q7-DYC2-WLRE-6..J

(Letters can be upper or lowercase)

So my question is, how can I reverse the hashes to get the full original message?

Any tips for me?