I now appears that Iran will not send the recorders to another country to be read.
From Reuters:
January 10, 2020 / 3:34 AM / Updated 17 minutes ago
Iran to analyze black box after missile blamed for crash
Alexander Cornwell,
Parisa Hafezi
DUBAI (Reuters) - Iran said on Friday it wanted to download black box recordings itself from a Ukrainian airliner that crashed, killing all 176 people aboard, after Canada and others said the plane was brought down by an Iranian missile, probably by mistake.
Iran, which has denied the Boeing 737-800 was downed by a missile, said it could take one or two months to extract information from the voice and flight data recorders. It said it could ask Russia, Canada, France or Ukraine if it needed help.
Tehran also said the probe might take one or two years.