OK ive always done the bass pedals in blast beats with just one foot (once in a blue moon itll be my spasticated left foot, but otherwise right) and ive always assumed others did it like this.
But when i saw cradle of filth at the underworld in lond a few months back ( shame on me) i noticed that adrian used both pedals instead of just one. Ive not tried it myself but i recon id probably spaz it up, going a much slower speed with my feet than my arms (cant say im a great drummer)
Also i downloaded a video of Frost rehearsing (Satyricon/1349/Keep of Kellesin) and he used one foot also.

You?

Hmm blastbeats, a subject i could talk about for hours!

At this moment any blastbeat under 280bpm (i.e anything on worlds) i do on one foot, either foot, depending on how i feel. i've got a variety of foot techniques i use at the moment too. I'm not playing anything over 280bpm at the moment, so i haven't had to 2 foot blast for ages.

When i recorded worlds i did lots of the blastbeats with 2 feet simply to make it tighter and to spread the work between both feet when playing all those super fast double bass parts interspersed with blasts.

On legions i did all the super fast blasts 280 bpm and above on 2 feet and all the ones around 280bpm and below on one foot.

Most bands don't play as fast as Mithras, we have some songs a lot faster than most of the big names of extreme metal, so when some of them boast about doing all one foot blasts, it's not particularly impressive given the slower tempos.

The drummer who inspired me the most was Pete Sandoval, who always does one foot blasts and always plays 16th notes on double sections, he can't be beat for bass drumming.

I'd advise you to carry on as you are and stick with using one foot blasts (make sure u use that left leg too). Sean (live drummer) does all his blasts on one foot, even the super fast ones