Some updates on this matter based on reading two books.
1. "Persian Fire" by Tom Holland, written in 2006 is a digestible recapitulation of the Persian Wars with the Greek city states in the 480s and 470s BC. Holland re-arranges the account of Herodotus to allow other connections to be made. I have not checked all of them, but I think he ran aground on an important one: the relationship of Astyages King of Media, Cyrus the future king of Persia, lieutenants of both individuals - and the subsequent King Darius I.
In book one of the Histories, Herodotus relates how Astyages, inspired by a dream directs Harpargos to murder the young prince Cyrus. Regarding the dream, Astyages had consulted magi on this matter.Harpagos, having failed in that, Astyages kidnaps his son, butchers him and serves him in a stew to his father. Harpargos continued to serve Astyages but stewed as well in his own anger. He worked tirelessly in behalf of Cyrus and confronted Astyages after Cyrus captured him in the field of battle. Subsequently he served Cyrus as a general in campaigns through Asia Minor.
In Herodotus, I can find no indication that Harpagos changed his name to Hystapes and became the father of Darius. Whether this is an error of Holland's, a pet theory or the tale of another ancient writer, I cannot say. But I certainly cannot find evidence to support this theory.
2.) "Ebla" right now appears to be the more interesting of the two books, though it might not be appropriately named. Archeologists and scholars of ancient Jewish life, Chaim Bermant and Michael Weitzman collaborate here, describing Italian work on Tell Mardikh in Syria near Aleppo and the background surrounding it. Ebla is rich in ancient cuneiform, best described for now as Proto-Canaanite from the 3rd millenium BC. Somewhat like the Dead Sea Scrolls, Ebla created excitement and anticipation for the public, especially with regard to the Pentateuch and possible connections to this hardly known city ( a few brief references in the OT). The third chapter of the book gives a broad 25 page survey of Biblical controversies over presumed anachronisms, sources such as J, E, P and D, the tribal heritages, contradictions, etc. Arguments posted are pro and con for "inerrancy" for lack of better term.
The fourth chapter was devoted to "Cuneiform without Tears" - and this is an exciting history of how the codes were cracked, starting with ancient Persian, largely off the testimony of Darius I in Behistun, Iran.
Rawlinson, a British army attache to the Persian government, cracked the code by comparing the genealogy provided by Herodotus, another tablet with a suspected list of kings ( Darius, Xerxes, king, king of kings, Persia... etc.). We finally get in English translation "Darius the Great King, King of Kings, King of countries, son of Hystaspes, an Achaemenian..."
Herodotus and Darius appear to be in agreement about both who his father was. Both Herodotus and Thucydides identify Medes as the invaders of Greece in 486 BC and Darius was king. Herodotus, as said above, calls out Xerxes as king of the Medes.
Now try to get Daniel to match like that with anything - save for predicting a perpetually receding event.