Thank you!
Zeno does give a full transliteration, which might be of help. :)
Central legend:
avyaktameka muhammada avatar nrpati mahamuda
Translation: The Invisible is One; Muhammad is the manifestation; Mahmud the king
Outside legend:
yam tankam mahamudapura ghatita ta jikiyera samvati
Translation: This tanka struck at Mahmudpur in the Arabic year 418
Written on this page:
https://www.zeno.ru/showphoto.php?photo=39207
I sent a request to add all that information to the page (the script, the transliteration, and the translation). If you would like to attempt to transcribe the rest of it, knowing what Zeno said about it might make that easier. :)