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Phone (Zenfone 6 ZS630KL) keeps booting into csc fastboot mode

Yavych
Star II
Hello. Today, my wife's phone stopped responding to anything out of blue. I did a forced reboot (Vol down + power) and it rebooted and worked fine for a bit. Seeing as Android 10 was out, I dled fota file and flashed it via recovery from SD card, like I usually do. It flashed successfully and then rebooted. Once it booted, after a few seconds it hanged and became unresponsive again. Forced reboot once again, except this time it booted into a fastboot mode on its own and here lies there problem:
- going through an option to get into recovery mode doesn't help as it goes back into fastboot mode again
- rebooting through cmd doesn't help either
- pressing start just returns to fastboot mode - shutting it down through an option in fastboot and then turning it on still yields the same result.
Basically, whenever phone turns on, it goes into a fastboot mode whether you want it or not.
Seems like update failed to flash into slot B
(bootloader) has-slot:system:yes
(bootloader) current-slot:a
(bootloader) has-slot:boot:yes
(bootloader) slot-retry-count:b:6
(bootloader) slot-unbootable:b:yes
(bootloader) slot-successful:b:yes
(bootloader) slot-retry-count:a:7
(bootloader) slot-unbootable:a:no
(bootloader) slot-successful:a:yes
(bootloader) slot-count:2
What can I do about this?
1 ACCEPTED SOLUTION

Accepted Solutions

Yavych
Star II
Okay, so I fixed it.
I flashed service/raw fw through fastboot, commenting out userdata formatting part of the flashall_aft script (fastboot -w). After this, I was able to access recovery mode. In recovery mode, I flashed build 16.1220.1909.194 and then 17.1810.1910.63 from my SD card and phone came alive, while retaining all the data.
Perhaps, this information will help someone who will encounter the same situation.

View solution in original post

10 REPLIES 10

LP_ASUS
Community Legend I

Yavych

Hello. Today, my wife's phone stopped responding to anything out of blue. I did a forced reboot (Vol down + power) and it rebooted and worked fine for a bit. Seeing as Android 10 was out, I dled fota file and flashed it via recovery from SD card, like I usually do. It flashed successfully and then rebooted. Once it booted, after a few seconds it hanged and became unresponsive again. Forced reboot once again, except this time it booted into a fastboot mode on its own and here lies there problem:

- going through an option to get into recovery mode doesn't help as it goes back into fastboot mode again

- rebooting through cmd doesn't help either

- pressing start just returns to fastboot mode - shutting it down through an option in fastboot and then turning it on still yields the same result.

Basically, whenever phone turns on, it goes into a fastboot mode whether you want it or not.

Seems like update failed to flash into slot B

(bootloader) has-slot:system:yes
(bootloader) current-slot:a
(bootloader) has-slot:boot:yes
(bootloader) slot-retry-count:b:6
(bootloader) slot-unbootable:b:yes
(bootloader) slot-successful:b:yes
(bootloader) slot-retry-count:a:7
(bootloader) slot-unbootable:a:no
(bootloader) slot-successful:a:yes
(bootloader) slot-count:2

What can I do about this?


Phone (Zenfone 6 ZS630KL) keeps booting into csc fastboot mode
As a layman with very minimal experience flashing Android phones, I would recommend contacting your regional ASUS Support for a repair.
Before that, I did a quick Google search and someone who had a similar issue apparently was able to stop the fastboot cycle by removing the SD card. Is that an option or have you already removed it?

Yavych
Star II
Hello, contacting local asus support is not an option.
Removing SD card doesn't anyhow help either.
I'd honestly try to just flash fw through fastboot into slot B, alas, that's not possible because device is locked.

LP_ASUS
Community Legend I
Yavych

Hello, contacting local asus support is not an option.

Removing SD card doesn't anyhow help either.

I'd honestly try to just flash fw through fastboot into slot B, alas, that's not possible because device is locked.


View post
That's why I'm thinking Support is your only option here. If you can't do anything on the software side because the device is locked in a loop, Support might need to arrange a swap for you.

Yavych
Star II
I can't do anything on a software side mostly because phone is factory locked, not because it's in a loop. If I could unlock bootloader through fastboot, I'd be able to flash FW into a slot B