Trezor 1 - Risk of upgrading firmware from 1.5.2 to 1.10.3 without seed

Hello everyone,
I’m on Trezor 1 with firmware 1.5.2. I can’t find my seed.
When I access my Trezor, only thing I can do is upgrade to 1.10.3.
I know I should not upgrade without seed but…
I can’t move my coins either as i can only run the firmware upgrade first.
What is the risk that the firmware upgrade goes wrong and I lose access to my Trezor ?

you must not only keep one copy of your seed
two more copies must be in different houses ,not homes ,houses !