Based on later comments in this thread I can now answer this myself:
Downgrade to a version with UMS support.
- Re: [Trisquel-users] Cannot get widescreen resolution a... simon . lydell
- Re: [Trisquel-users] Cannot get widescreen resolut... maestro
- Re: [Trisquel-users] Cannot get widescreen resolut... maestro
- Re: [Trisquel-users] Cannot get widescreen res... Michał Masłowski
- Re: [Trisquel-users] Cannot get widescreen... simon . lydell
- Re: [Trisquel-users] Cannot get widesc... Michał Masłowski
- Re: [Trisquel-users] Cannot get w... simon . lydell
- Re: [Trisquel-users] Cannot g... simon . lydell
- Re: [Trisquel-users] Cannot get w... simon . lydell
- Re: [Trisquel-users] Cannot g... Michał Masłowski
- Re: [Trisquel-users] Cann... simon . lydell
- Re: [Trisquel-users] Cann... maestro
- Re: [Trisquel-users] Cann... simon . lydell
- Re: [Trisquel-users] Cannot get widescreen resolut... simon . lydell