This claim is wrong because actually all the FDR system has been updated before 08/18/2001...
According to
http://www.boeing.com/commercial/aer...ly/s01txt.html
Airplanes manufactured before October 11, 1991, without an FDAU or DFDAU as of July 16, 1996.
Airplanes manufactured before October 11, 1991, with an FDAU or DFDAU as of July 16, 1996.
Airplanes manufactured after October 11, 1991, after August 18, 2000, and after August 18, 2002.
AIRPLANES MANUFACTURED PRIOR TO OCTOBER 11, 1991, WITHOUT AN FDAU OR DFDAU INSTALLED AS OF JULY 16, 1996.
The new rule requires that by August 18, 2001 the FDR record at least 18 parameter groups. For most airplanes, this is an increase from 11 parameter groups, as described in "Effects of 1989 FAA Flight Data Recorder Rule Change" on page 32.
The new rule requires that by four years from date of rule at least 22 parameter groups be recorded by the FDR. In this group are Boeing models 727, 737, 747, 757, 767, DC-10, and MD-80.
Flight 77 = N644AA 2460
Certificate Issue Date 05/08/1991
FAA Registry - Aircraft - N-Number Inquiry
N644AA = AIRPLANES MANUFACTURED PRIOR TO OCTOBER 11, 1991
So N644AA has been updated before August 18, 2001