[One (M7) Android Development] r.ciesla:
Works like a charm! Many thanks for that!

Flashed successfully however progress bar stuck at the end... but pheeeeew... still alive :D

C:\Android>adb reboot bootloader

C:\Android>fastboot oem rebootRUU

...

(bootloader) Start Verify: 0

OKAY [ 0.049s]

finished. total time: 0.060s

C:\Android>fastboot flash zip firmware.zip

sending 'zip' (29318 KB)...

OKAY [ 2.477s]

writing 'zip'...

(bootloader) zip header checking...

(bootloader) zip info parsing...

(bootloader) checking model ID...

(bootloader) checking custom ID...

(bootloader) start image[hboot] unzipping for pre-update check...

(bootloader) start image[hboot] flushing...

(bootloader) [RUU]WP,hboot,0

(bootloader) [RUU]WP,hboot,99

(bootloader) [RUU]WP,hboot,100

(bootloader) ...... Successful

FAILED (remote: 90 hboot pre-update! please flush image again immediately)

finished. total time: 4.093s

C:\Android>fastboot flash zip firmware.zip

sending 'zip' (29318 KB)...

OKAY [ 2.518s]

writing 'zip'...

(bootloader) zip header checking...

(bootloader) zip info parsing...

(bootloader) checking model ID...

(bootloader) checking custom ID...

(bootloader) start image[adsp] unzipping & flushing...

(bootloader) [RUU]UZ,adsp,0

(bootloader) [RUU]UZ,adsp,15

(bootloader) [RUU]UZ,adsp,27

(bootloader) [RUU]UZ,adsp,38

(bootloader) [RUU]UZ,adsp,49

(bootloader) [RUU]UZ,adsp,60

(bootloader) [RUU]UZ,adsp,72

(bootloader) [RUU]UZ,adsp,83

(bootloader) [RUU]UZ,adsp,94

(bootloader) [RUU]UZ,adsp,100

(bootloader) [RUU]WP,adsp,0

(bootloader) [RUU]WP,adsp,100

(bootloader) ...... Successful

(bootloader) start image[cir] unzipping & flushing...

(bootloader) [RUU]UZ,cir,0

(bootloader) [RUU]UZ,cir,100

(bootloader) ...... Successful

(bootloader) start image[pg2fs_spcustom] unzipping & flushing...

(bootloader) [RUU]UZ,pg2fs_spcustom,0

(bootloader) [RUU]UZ,pg2fs_spcustom,22

(bootloader) [RUU]UZ,pg2fs_spcustom,48

(bootloader) [RUU]UZ,pg2fs_spcustom,70

(bootloader) [RUU]UZ,pg2fs_spcustom,97

(bootloader) [RUU]UZ,pg2fs_spcustom,100

(bootloader) ...... Successful

(bootloader) start image[rpm] unzipping & flushing...

(bootloader) [RUU]UZ,rpm,0

(bootloader) [RUU]UZ,rpm,100

(bootloader) [RUU]WP,rpm,0

(bootloader) [RUU]WP,rpm,100

(bootloader) ...... Successful

(bootloader) start image[sbl1-1] unzipping & flushing...

(bootloader) [RUU]UZ,sbl1-1,0

(bootloader) [RUU]UZ,sbl1-1,100

(bootloader) signature checking...

(bootloader) verified fail

(bootloader) ..... Bypassed

(bootloader) start image[sbl1-2] unzipping & flushing...

(bootloader) [RUU]UZ,sbl1-2,0

(bootloader) [RUU]UZ,sbl1-2,100

(bootloader) signature checking...

(bootloader) verified fail

(bootloader) ..... Bypassed

(bootloader) start image[sbl1-3] unzipping & flushing...

(bootloader) [RUU]UZ,sbl1-3,0

(bootloader) [RUU]UZ,sbl1-3,100

(bootloader) signature checking...

(bootloader) [RUU]WP,sbl1-3,0

(bootloader) [RUU]WP,sbl1-3,100

(bootloader) ...... Successful

(bootloader) start image[sbl2] unzipping & flushing...

(bootloader) [RUU]UZ,sbl2,0

(bootloader) [RUU]UZ,sbl2,100

(bootloader) [RUU]WP,sbl2,0

(bootloader) [RUU]WP,sbl2,100

(bootloader) ...... Successful

(bootloader) start image[sbl3] unzipping & flushing...

(bootloader) [RUU]UZ,sbl3,0

(bootloader) [RUU]UZ,sbl3,100

(bootloader) [RUU]WP,sbl3,0

(bootloader) [RUU]WP,sbl3,100

(bootloader) ...... Successful

(bootloader) start image[sp1] unzipping & flushing...

(bootloader) [RUU]UZ,sp1,0

(bootloader) [RUU]UZ,sp1,24

(bootloader) [RUU]UZ,sp1,46

(bootloader) [RUU]UZ,sp1,69

(bootloader) [RUU]UZ,sp1,94

(bootloader) [RUU]UZ,sp1,100

(bootloader) [RUU]WP,sp1,0

(bootloader) [RUU]WP,sp1,100

(bootloader) ...... Successful

(bootloader) start image[tp] unzipping & flushing...

(bootloader) [RUU]UZ,tp,0

(bootloader) [RUU]UZ,tp,100

(bootloader) ...... Successful

(bootloader) start image[tz] unzipping & flushing...

(bootloader) [RUU]UZ,tz,0

(bootloader) [RUU]UZ,tz,100

(bootloader) [RUU]WP,tz,0

(bootloader) [RUU]WP,tz,100

(bootloader) ...... Successful

(bootloader) start image[radio] unzipping & flushing...

(bootloader) [RUU]UZ,radio,0

(bootloader) [RUU]UZ,radio,5

(bootloader) [RUU]UZ,radio,11

(bootloader) [RUU]UZ,radio,17

(bootloader) [RUU]UZ,radio,23

(bootloader) [RUU]UZ,radio,29

(bootloader) [RUU]UZ,radio,34

(bootloader) [RUU]UZ,radio,40

(bootloader) [RUU]UZ,radio,46

(bootloader) [RUU]UZ,radio,52

(bootloader) [RUU]UZ,radio,58

(bootloader) [RUU]UZ,radio,63

(bootloader) [RUU]UZ,radio,69

(bootloader) [RUU]UZ,radio,75

(bootloader) [RUU]UZ,radio,81

(bootloader) [RUU]UZ,radio,86

(bootloader) [RUU]UZ,radio,92

(bootloader) [RUU]UZ,radio,98

(bootloader) [RUU]UZ,radio,100

(bootloader) [RUU]WP,radio,0

(bootloader) [RUU]WP,radio,23

(bootloader) [RUU]WP,radio,46

(bootloader) [RUU]WP,radio,69

(bootloader) [RUU]WP,radio,92

(bootloader) [RUU]WP,radio,100

(bootloader) ...... Successful

(bootloader) start image[rcdata] unzipping & flushing...

(bootloader) [RUU]UZ,rcdata,0

(bootloader) [RUU]WP,rcdata,0

(bootloader) ...... Successful

OKAY [ 51.831s]

finished. total time: 54.351s

C:\Android>fastboot reboot-bootloader

rebooting into bootloader...

OKAY [ 0.034s]

finished. total time: 0.035s

C:\Android>fastboot getvar all

(bootloader) version: 0.5

(bootloader) version-bootloader: 1.55.0000

(bootloader) version-baseband: 4T.20.3218.03

(bootloader) version-cpld: None

(bootloader) version-microp: None

(bootloader) version-main: 3.17.401.2

(bootloader) version-misc: PVT SHIP S-OFF

(bootloader) serialno: HT35********

(bootloader) imei: 35***********86

(bootloader) meid: 00000000000000

(bootloader) product: m7_ul

(bootloader) platform: HBOOT-8064

(bootloader) modelid: PN0714000

(bootloader) cidnum: HTC__001

(bootloader) battery-status: good

(bootloader) battery-voltage: 4218mV

(bootloader) partition-layout: Generic

(bootloader) security: off

(bootloader) build-mode: SHIP

(bootloader) boot-mode: RUU

(bootloader) commitno-bootloader: dirty-2da61e5e88

(bootloader) hbootpreupdate: 11

(bootloader) gencheckpt: 0

all: Done!

finished. total time: 0.065s

C:\Android>fastboot erase cache

erasing 'cache'...

OKAY [ 0.080s]

finished. total time: 0.081s

C:\Android>fastboot reboot

rebooting...

finished. total time: 0.042s