Here is another successful case study of Seagate ST1000LM035 HDD firmware repair and data recovery, where the LED wasn't detected.

HDD Details:

Model: ST1000LM035 1RK172
Family: Rosewood A5

Error Messages in COM Terminal:

‘Boot 0x80M
QB
Rst 0x80M
Srv DETCR init 0x0000

FTU

(P) SATA Reset

RAW OFF

PASS

(DOS Table) Worst Count: 00000FF8 At SU: 0000523E NT: 00000000 OT: 000000C5
(MC POR Duration): 000000007B

Intel 6G->3G

Send Status: COMRESET seen

CSpd= 3Gbps

DSC

Update Mask – 000000000D0A3EB8 – 00000008 – 00

Update Mask – 000000000D0A3EC0 – 00000008 – 00

Starting LBA of RW Request=0001A13C9F Length=00001DD0

ProcessRWError -Read- at LBA 0001A147F9 Sense Code=43110081

Common path start quit now
ProcessRC: 00000000,00000000
SkipLen: 00000000
ReadContinuous: 01A1468F,00000350
UnrecovSectorCount:002B,0236
NumUDEs: 0000002B,00000031,00000236
Passed: 00000080,00000153,000002FB
Out:

PrgF

LED:0x000000BD FAddr:0x0000780F
LED:0x000000BD FAddr:0x0000780F
LED:0x000000BD FAddr:0x0000780F’