In 2017 after football quarterback, Colin Kaepernick, knelt during the National Anthem in protest of police brutality and racism against African-Americans in the United States, there were serveral articles looking back at Hendrix rendition of the national anthem almost 50 years earlier as the closing act at
Woodstock, "an Aquarian Exposition: 3 Days of Peace & Music" in 1969, where hew was a headliner along with Joan Baez, Santana, the Grateful Dead, Creedence Clearwater Revival, Janis Joplin, Arlo Guthrie, Jefferson Airplane, Blood, Sweat & Tears, Crosby, Stills, Nash & Young and more. More than 400,000 people attended the concert in an open field on a dairy farm in Bethel, New York.
Was it a similar act of protest?

  Rain delays pushed Hendrix program into Monday, and a lot of people had left.
After a two hour set he played his regular concert-closer, "Voodoo Child (Slight Return). He then made a rare decision to perform an encore, and a mid-set medley that featured this solo rip at "The Star-Spangled Banner" on his Fender Stratocaster.
In his memoir, Hendrix's drummer, Mitch Mitchell, admitted that the band "hadn't rehearsed ... or planned to do 'The Star-Spangled Banner' at Woodstock."

He died from barbiturate-related asphyxia a year later.

The Rock and Roll Hall of Fame describes him as "the greatest instrumentalist in the history of rock music".


Links:

Protest and patriotism: a visit to the original star-spangled banner | US news | The Guardian
Setlist History: On This Day in 1969, Jimi Hendrix Closed Woodstock | setlist.fm
Patriotism or protest? Army vet Jimi Hendrix had the 'most electrifying moment' at Woodstock - 1969 - Stripes
Hendrix Breaks Down 'Star-Spangled Banner' Woodstock Show: Watch - Rolling Stone
Hendrix and Woodstock: 10 Little-Known Facts about the Performance That Defined the '60s | News | WPI