Vale mira de nuevo, ese es el proceso que hago yo, no se si estará mal... bueno aquí el resultado.
Intento 1
C:\platform-tools>fastboot devices
HT49GW900422 fastboot
C:\platform-tools>fastboot oem rebootRUU
...
(bootloader) Start Verify: 3
OKAY [ 0.041s]
finished. total time: 0.042s
C:\platform-tools>fastboot flash zip ruu.zip
target reported max download size of 1542111232 bytes
sending 'zip' (1304199 KB)...
OKAY [ 43.725s]
writing 'zip'...
(bootloader) signature checking...
FAILED (remote: 12 signature verify fail)
finished. total time: 174.779s
Archivo PN07IMG_M7C_DUG_L50_SENSE60_MR_HTC_Europe_7.17.401 .5_Radio_1237.29.35.0903_release_425785_signed.zip
------------------
Intento 2
C:\platform-tools>fastboot reboot-bootloader
rebooting into bootloader...
OKAY [ 0.044s]
finished. total time: 0.046s
C:\platform-tools>fastboot devices
HT49GW900422 fastboot
C:\platform-tools>fastboot oem rebootRUU
...
(bootloader) Start Verify: 3
OKAY [ 0.035s]
finished. total time: 0.036s
C:\platform-tools>fastboot flash zip ruu.zip
target reported max download size of 1542111232 bytes
sending 'zip' (1304192 KB)...
OKAY [ 43.732s]
writing 'zip'...
(bootloader) signature checking...
FAILED (remote: 12 signature verify fail)
finished. total time: 165.182s
Archivo PN07IMG_M7C_DUG_L50_SENSE60_MR_HTC_Nordic_7.17.402 .5_Radio_E1237.29.35.0108_release_425799_signed.zi p
Mismo resultado,
Igualmente gracias men, por el apoyo... ya queda resignarme, esperar el día que se pueda... Saludos