[One (M7) General] yasir.t.mohmand:
Already done that. No use. Same problem. Going to try this one now. By the way, after S-off, should the bootloader be in relocked or unlocked condition for this tutorial? Because back in the same topic somewhere I saw one saying it should be locked, other said unlocked. Which one is it?

Hello,

first of all it's a great forum!

Many thanks to postings from shwetkprabhat and wewenk!

Finally summarizing the single informations and try to put them together was my success.

For all other I will summarize in one posting how to proceed.

Initial situation for me:

Because I was already on HBOOT 2.49 I unblock my bootloader via HTCdev.

After that I was able to apply firewater to get my phone S-OFF.

I assume that the unlocked bootloader is a must have to survive.

Otherwise it is not possible to set the phone S-OFF to change the cid.

CID HTC__A07 is a must have that subsequent workflow will work.

After that I had following information inside my Bootloader screen:

CID: HTCCN703

HBOOT: 2.49

OS: 4.21.1402.5

Target was to reach:

CID: HTC__A07

HBOOT: 2.49

OS: 4.21.401.5

Because I'm new I'm not allowed to post the links. Sorry.

Subsequent the packages you need to survive:

h t t p://d-h.st/xtM : HBOOT 2.49 + 4.4.2 Stock Recovery.7z - 14.27 MB

h t t p://d-h.st/a8L : FIRMWARE_M7C_DUG_JB_50_S1_HTC_Europe_2.41.401.1.zi p - 45.32 MB

h t t p://d-h.st/3Cd : PN07IMG_M7C_DUG_JB_50_S1_HTC_Europe_2.19.401.1_Rad io_1237.21.28.0627_release_326125.zip - 989.19 MB

h t t p://d-h.st/MvF : OTA_M7C_DUG_JB_50_S1_HTC_Europe_2.41.401.1-2.19.401.1_release_3398289.zip - 131.61 MB

h t t p://d-h.st/q0t : OTA_M7C_DUG_K44_SENSE55_MR_HTC_Europe_4.21.401.5-2.41.401.1_release_355886.zip - 867.93 MB

For all update operations I use an external SD-Card.

I use HBOOT mode or Recovery mode to apply the new software. As long an update is not fully done (mainly one or two reboots of the phone needed) keep the SD-Card inside the phone.

What has to be done now (with same initial start point like mine):

1. Get the HTCdev-unlock_bootloader.zip file from HTCdev like I did and unblock the bootloader like it is explained on HTCdev

2. Root your phone and use firewater to make your phone S-OFF (enough explanations available)

3. Use fastboot and set your cid to HTC__A07: fastboot oem writecid HTC__A07

4. Copy content of HBOOT 2.49 + 4.4.2 Stock Recovery.7z - 14.27 MB as PN07IMG.zip to the root of the SD-Card

5. Insert the SD-Card and reboot the phone into the bootloader

6. The PN07IMG.zip (4.) will be found and you get asked to apply the update or not. Apply with pressing Vol-Up button

7. After Update is fully applied detach the SD-Card from the phone

8. Copy FIRMWARE_M7C_DUG_JB_50_S1_HTC_Europe_2.41.401.1.zi p - 45.32 MB as PN07IMG.zip to the root of your SD-Card

9. Insert the SD-Card and reboot the phone into the bootloader

10. The PN07IMG.zip (8.) will be found and you get asked to apply the update or not. Apply with pressing Vol-Up button

11. After on additional reboot the firmware is fully applied. Detach the SD-Card from the phone.

12. The bootloader should show you now HBOOT 2.27 and OS 2.41.401.1

13. Copy PN07IMG_M7C_DUG_JB_50_S1_HTC_Europe_2.19.401.1_Rad io_1237.21.28.0627_release_326125.zip - 989.19 MB as PN07IMG.zip to the root of your SD-Card.

14. Insert the SD-Card and reboot the phone into the bootloader

15. The PN07IMG.zip (13.) will be found and you get asked to apply the update or not. Apply with pressing Vol-Up button

16. After on additional reboot the firmware is fully applied. Detach the SD-Card from the phone.

17. The phone will start-up now with 2.19.401.1

18. Switch off the phone and boot into the bootloader

19. The bootloader should show you now HBOOT 2.26 and OS 2.19.401.1

20. Delete all other ZIP files from your SD-Card and copy OTA_M7C_DUG_JB_50_S1_HTC_Europe_2.41.401.1-2.19.401.1_release_3398289.zip - 131.61 MB as OTA.zip to the root of the SD-Card.

21. Insert the SD-Card into your phone

22. Start the Recovery mode from the Bootloader menu

23. After that you will see the screen with phone and red exclamation mark press Vol-Up and Power button for at least 2 seconds and release them. You should get on top of the screen a menu. If it will not work with the first try - try it again.

24. Choose the second menu entry "Update from SD-Card" (not exactly but you will find it)

25. Choose the OTA.zip (20.) and commit with pressing the power button

26. After update is fully applied the phone should boot into the normal OS. Detach the SD-Card from the phone

27. Copy OTA_M7C_DUG_K44_SENSE55_MR_HTC_Europe_4.21.401.5-2.41.401.1_release_355886.zip - 867.93 MB as OTA.zip to the root of your SD-Card

28. Switch off the phone

29. Boot the phone into the bootloader

30. Start the Recovery mode from the Bootloader menu

31. After that you will see the screen with phone and red exclamation mark press Vol-Up and Power button for at least 2 seconds and release them. You should get on top of the screen a menu. If it will not work with the first try - try it again.

32. Choose the second menu entry "Update from SD-Card" (not exactly but you will find it)

33. Choose the OTA.zip (27.) and commit with pressing the power button

34. The phone will apply the update. Inside the recovery screen you get asked to commit the update with a new firmware.zip. Commit this and the update process continuous.

35. After the update is fully applied you are on HBOOT 2.49 and 4.21.401.5

Enjoy!

I hope my explanation is good enough and will help.

Now I have only to apply the SU. Because Android 4.4.x has a very big drawback. External installed apps (google store) cannot access the SD-Card with write access. That's of course a no go.