Yes, he didn't even know scales. That did cause issues when he was supposed to replicate Blackmore's signature moody and dark neo-classical solos on stuff like Highway Star and Burn note for note on the few songs Purple retained from their old set (80% of the set was Come Taste The Band and even Bolin solo material). He just couldn't and didn't. Asian, Oceanian and US audiences were forgiving about that - in the UK, where Blackmore was regarded as somewhat of a deity, it fell flat on its arse. Bolin got booed and at the end of the UK tour (which initially was supposed to continue into Continental Europe after a short break), Coverdale, Lord and Paice threw the towel without telling Bolin and Hughes. The reviews had been scathing and I remember letters in the NME by enraged heavy metal fans comparing Tommy unfavorably to Ace Frehley as Kiss were touring the UK for the first time around then too.
Martin Birch, the longstanding DP engineer and producer, said that unlike Ritchie who would often retreat to work things out, Bolin "relied entirely on feel". But while he was relaxed and even experimental/overdub-happy in the studio, he froze on stage if an audience did not immediately take to him. And British audiences especially were feared as jaded, aloof and spoilt.