Hi,
i want to make a rollback from eOS (1.5.1S) to stock FP4 OS. I open the OEM, unlock the bootloader. Boot into Fastboot Mode. After activating the flash bat script i input “YES” to install stock rom. After that the window closes and nothing happens. What do i wrong?
greetings
Thats a bug in the Windows script…
And welcome to the community
Thank you very much! 
Must i carefull because i am on android 12 with eOS and the stock rom is on android 11?
I personally would always be extremly careful with locking the bootloader, not to say I would currently most likely not lock the bootloader…
See here, especially search for hints regarding
get unlock ability
The Installation works well. Thank you for your very good help.
I have restart the evice with ./adb reboot bootloader (that works)
Now i want to lock the bootloader again, but the adb output says:
fastboot: usage: unknown ‘flashing’ command lock_critcal
You’ve to use “fastboot” (and not “adb”) to relock your device (resp. which command exactly did you use?)
Have you made sure “get unlock ability” is “1” (just to be sure you can’t brick your device…)?
yes, i know i have type:
./fastboot flashing lock_critcal
then the output says:
fastboot: usage: unknown ‘flashing’ command lock_critcal
can you explain get unlock ability?
Is the fastboot version up-to-date?
And your phone is connectected and in fastboot mode (fastboot devices gives some id as output)?
Just type
fastboot flashing get_unlock_ability
and check the output. To be safe it should be “1”. If all goes fine you might still change oem unlock later.
Or you boot your phone and check the setting of “OEM unlock” in the “developer options” in settings.
./fastboot flashing get_unlock_ability
(bootloader) get_unlock_ability: 0
OKAY [ 0.003s]
Finished. Total time: 0.004s
Now the device don’t start again. i can only boot to bootloader (fastboot mode) 
Did i brick my device now? Oh my god…
./fastboot flashing get_unlock_ability can’t brick your device. It’s only reading a flag.
As long as your device is not yet locked it’s not bricked. You can always reinstall it.
Maybe you post the output of fastboot getvar all so it shows the status.
(bootloader) parallel-download-flash:yes
(bootloader) hw-revision:10000
(bootloader) unlocked:no
(bootloader) off-mode-charge:0
(bootloader) charger-screen-enabled:0
(bootloader) battery-soc-ok:yes
(bootloader) battery-voltage:4089
(bootloader) version-baseband:
(bootloader) version-bootloader:
(bootloader) erase-block-size: 0x1000
(bootloader) logical-block-size: 0x1000
(bootloader) variant:SM_ UFS
(bootloader) partition-type:modemst2:raw
(bootloader) partition-size:modemst2: 0x600000
(bootloader) partition-type:modemst1:raw
(bootloader) partition-size:modemst1: 0x600000
(bootloader) partition-type:tunning:raw
(bootloader) partition-size:tunning: 0x600000
(bootloader) partition-type:fsc:raw
(bootloader) partition-size:fsc: 0x20000
(bootloader) partition-type:fsg:raw
(bootloader) partition-size:fsg: 0x280000
(bootloader) partition-type:fpconfig:raw
(bootloader) partition-size:fpconfig: 0x20000
(bootloader) partition-type:fpconfig_persist:raw
(bootloader) partition-size:fpconfig_persist: 0x20000
(bootloader) partition-type:traceability:raw
(bootloader) partition-size:traceability: 0x100000
(bootloader) partition-type:ALIGN_TO_128K_2:raw
(bootloader) partition-size:ALIGN_TO_128K_2: 0x1A000
(bootloader) partition-type:swversion:raw
(bootloader) partition-size:swversion: 0x20000
(bootloader) partition-type:oembin:raw
(bootloader) partition-size:oembin: 0x400000
(bootloader) partition-type:catecontentfv:raw
(bootloader) partition-size:catecontentfv: 0x100000
(bootloader) partition-type:catefv:raw
(bootloader) partition-size:catefv: 0x80000
(bootloader) partition-type:secdata:raw
(bootloader) partition-size:secdata: 0x7000
(bootloader) partition-type:uefivarstore:raw
(bootloader) partition-size:uefivarstore: 0x80000
(bootloader) partition-type:storsec:raw
(bootloader) partition-size:storsec: 0x20000
(bootloader) partition-type:logdump:raw
(bootloader) partition-size:logdump: 0x4000000
(bootloader) partition-type:cateloader:raw
(bootloader) partition-size:cateloader: 0x200000
(bootloader) partition-type:logfs:raw
(bootloader) partition-size:logfs: 0x800000
(bootloader) partition-type:toolsfv:raw
(bootloader) partition-size:toolsfv: 0x100000
(bootloader) partition-type:limits-cdsp:raw
(bootloader) partition-size:limits-cdsp: 0x1000
(bootloader) partition-type:limits:raw
(bootloader) partition-size:limits: 0x1000
(bootloader) partition-type:splash:raw
(bootloader) partition-size:splash: 0x20A4000
(bootloader) partition-type:spunvm:raw
(bootloader) partition-size:spunvm: 0x800000
(bootloader) partition-type:apdp:raw
(bootloader) partition-size:apdp: 0x40000
(bootloader) partition-type:dip:raw
(bootloader) partition-size:dip: 0x100000
(bootloader) partition-type:devinfo:raw
(bootloader) partition-size:devinfo: 0x1000
(bootloader) partition-type:fsgbk_b:raw
(bootloader) partition-size:fsgbk_b: 0x280000
(bootloader) partition-type:core_nhlos_b:raw
(bootloader) partition-size:core_nhlos_b: 0xAA00000
(bootloader) partition-type:uefisecapp_b:raw
(bootloader) partition-size:uefisecapp_b: 0x200000
(bootloader) partition-type:imagefv_b:raw
(bootloader) partition-size:imagefv_b: 0x200000
(bootloader) partition-type:featenabler_b:raw
(bootloader) partition-size:featenabler_b: 0x20000
(bootloader) partition-type:dtbo_b:raw
(bootloader) partition-size:dtbo_b: 0x1800000
(bootloader) partition-type:vbmeta_b:raw
(bootloader) partition-size:vbmeta_b: 0x10000
(bootloader) partition-type:vbmeta_system_b:raw
(bootloader) partition-size:vbmeta_system_b: 0x10000
(bootloader) partition-type:recovery_b:raw
(bootloader) partition-size:recovery_b: 0x6000000
(bootloader) partition-type:qupfw_b:raw
(bootloader) partition-size:qupfw_b: 0x14000
(bootloader) partition-type:devcfg_b:raw
(bootloader) partition-size:devcfg_b: 0x20000
(bootloader) partition-type:boot_b:raw
(bootloader) partition-size:boot_b: 0x6000000
(bootloader) partition-type:keymaster_b:raw
(bootloader) partition-size:keymaster_b: 0x80000
(bootloader) partition-type:dsp_b:raw
(bootloader) partition-size:dsp_b: 0x4000000
(bootloader) partition-type:abl_b:raw
(bootloader) partition-size:abl_b: 0x100000
(bootloader) partition-type:mdtp_b:raw
(bootloader) partition-size:mdtp_b: 0x2000000
(bootloader) partition-type:mdtpsecapp_b:raw
(bootloader) partition-size:mdtpsecapp_b: 0x400000
(bootloader) partition-type:bluetooth_b:raw
(bootloader) partition-size:bluetooth_b: 0x200000
(bootloader) partition-type:modem_b:raw
(bootloader) partition-size:modem_b: 0xC300000
(bootloader) partition-type:hyp_b:raw
(bootloader) partition-size:hyp_b: 0x80000
(bootloader) partition-type:multiimgoem_b:raw
(bootloader) partition-size:multiimgoem_b: 0x8000
(bootloader) partition-type:tz_b:raw
(bootloader) partition-size:tz_b: 0x400000
(bootloader) partition-type:aop_b:raw
(bootloader) partition-size:aop_b: 0x80000
(bootloader) partition-type:questdatafv:raw
(bootloader) partition-size:questdatafv: 0x1000000
(bootloader) partition-type:fsgbk_a:raw
(bootloader) partition-size:fsgbk_a: 0x280000
(bootloader) partition-type:featenabler_a:raw
(bootloader) partition-size:featenabler_a: 0x20000
(bootloader) partition-type:core_nhlos_a:raw
(bootloader) partition-size:core_nhlos_a: 0xAA00000
(bootloader) partition-type:uefisecapp_a:raw
(bootloader) partition-size:uefisecapp_a: 0x200000
(bootloader) partition-type:imagefv_a:raw
(bootloader) partition-size:imagefv_a: 0x200000
(bootloader) partition-type:dtbo_a:raw
(bootloader) partition-size:dtbo_a: 0x1800000
(bootloader) partition-type:vbmeta_a:raw
(bootloader) partition-size:vbmeta_a: 0x10000
(bootloader) partition-type:vbmeta_system_a:raw
(bootloader) partition-size:vbmeta_system_a: 0x10000
(bootloader) partition-type:recovery_a:raw
(bootloader) partition-size:recovery_a: 0x6000000
(bootloader) partition-type:qupfw_a:raw
(bootloader) partition-size:qupfw_a: 0x14000
(bootloader) partition-type:devcfg_a:raw
(bootloader) partition-size:devcfg_a: 0x20000
(bootloader) partition-type:boot_a:raw
(bootloader) partition-size:boot_a: 0x6000000
(bootloader) partition-type:keymaster_a:raw
(bootloader) partition-size:keymaster_a: 0x80000
(bootloader) partition-type:dsp_a:raw
(bootloader) partition-size:dsp_a: 0x4000000
(bootloader) partition-type:abl_a:raw
(bootloader) partition-size:abl_a: 0x100000
(bootloader) partition-type:mdtp_a:raw
(bootloader) partition-size:mdtp_a: 0x2000000
(bootloader) partition-type:mdtpsecapp_a:raw
(bootloader) partition-size:mdtpsecapp_a: 0x400000
(bootloader) partition-type:bluetooth_a:raw
(bootloader) partition-size:bluetooth_a: 0x200000
(bootloader) partition-type:modem_a:raw
(bootloader) partition-size:modem_a: 0xC300000
(bootloader) partition-type:hyp_a:raw
(bootloader) partition-size:hyp_a: 0x80000
(bootloader) partition-type:multiimgoem_a:raw
(bootloader) partition-size:multiimgoem_a: 0x8000
(bootloader) partition-type:tz_a:raw
(bootloader) partition-size:tz_a: 0x400000
(bootloader) partition-type:aop_a:raw
(bootloader) partition-size:aop_a: 0x80000
(bootloader) partition-type:ALIGN_TO_128K_4:raw
(bootloader) partition-size:ALIGN_TO_128K_4: 0x1A000
(bootloader) partition-type:ddr:raw
(bootloader) partition-size:ddr: 0x100000
(bootloader) partition-type:cdt:raw
(bootloader) partition-size:cdt: 0x20000
(bootloader) partition-type:ALIGN_TO_128K_1:raw
(bootloader) partition-size:ALIGN_TO_128K_1: 0x1A000
(bootloader) partition-type:xbl_config_b:raw
(bootloader) partition-size:xbl_config_b: 0x20000
(bootloader) partition-type:xbl_b:raw
(bootloader) partition-size:xbl_b: 0x380000
(bootloader) partition-type:xbl_config_a:raw
(bootloader) partition-size:xbl_config_a: 0x20000
(bootloader) partition-type:xbl_a:raw
(bootloader) partition-size:xbl_a: 0x380000
(bootloader) partition-type:userdata:ext4
(bootloader) partition-size:userdata: 0x377E72E000
(bootloader) partition-type:super:raw
(bootloader) partition-size:super: 0x180000000
(bootloader) partition-type:rawdump:raw
(bootloader) partition-size:rawdump: 0x20CCCD000
(bootloader) partition-type:oempersist:raw
(bootloader) partition-size:oempersist: 0xC800000
(bootloader) partition-type:metadata:raw
(bootloader) partition-size:metadata: 0x1DE0000
(bootloader) partition-type:frp:raw
(bootloader) partition-size:frp: 0x80000
(bootloader) partition-type:keystore:raw
(bootloader) partition-size:keystore: 0x80000
(bootloader) partition-type:misc:raw
(bootloader) partition-size:misc: 0x100000
(bootloader) partition-type:persist:raw
(bootloader) partition-size:persist: 0x2000000
(bootloader) partition-type:ssd:raw
(bootloader) partition-size:ssd: 0x2000
(bootloader) partition-type:ALIGN_TO_128K_3:raw
(bootloader) partition-size:ALIGN_TO_128K_3: 0x18000
(bootloader) has-slot:modem:yes
(bootloader) has-slot:system:no
(bootloader) current-slot:a
(bootloader) has-slot:boot:yes
(bootloader) slot-retry-count:b:7
(bootloader) slot-unbootable:b:no
(bootloader) slot-successful:b:no
(bootloader) slot-retry-count:a:6
(bootloader) slot-unbootable:a:yes
(bootloader) slot-successful:a:yes
(bootloader) slot-count:2
(bootloader) secure:yes
(bootloader) serialno:768de66d
(bootloader) product:FP4
(bootloader) snapshot-update-status:none
(bootloader) is-userspace:no
(bootloader) max-download-size:805306368
(bootloader) kernel:uefi
all:
Finished. Total time: 0.329s
this is the output…
Well, it shows “unlocked: no”, so it seems you’ve already locked your device (I think your command fastboot flashing lock had succeeded and you’d confirmed locking on the phone itself…).
And it also shows “slot a bootable: no”. So I think you only might try to reboot your device various times until it switches to slot b and hope it boots then…
can i switch manually to slot b?
Only as long as the bootloader is unlocked.
i see, i must contact the support i think… 
Maybe someone else still has a good idea. But for me it doesn’t look very well, sorry 
2022-12-17T20:00:00Z
Hello Everyone.
I’m having trouble installing the Fairphone OS on my FP4. Let me explain:
I’ve been using Calyx OS for the past few months but now I want to go back to Fairphone OS. I’m terefore following the instructions of these articles: https://support.fairphone.com/hc/en-us/articles/4405858261777
https://support.fairphone.com/hc/en-us/articles/4433978210833
I’ve unlocked my bootloader (fastboot mode → device state - unlocked)
I’ve installed all of the lastest drivers and updates
I’ve downloaded the lasted version of the OS as mentionned on the fairphone article. Version: FP4.FP4G.A.170.20220920
I then run “flash_fp4_factory” batch file until the following message:
WARNING: Flashing this image wipes all user data and settings on the phone.
It will also remove the Google factory reset protection.
Are you sure you want to continue?
Type “Yes” (case sensitive) and press enter to continue: ¨
Then I type “yes” and the script crash and closes. Nothing happens afterwards…
I’ve tried many things (changing my USB cable, changing my computer USB port, changing fastboot from a to b and vice-versa, etc.) but can’t find a solution.
Can someone help me?
Many thanks in advance 
Hi, I moved your post here. Please see the solution above, there is a bug on the windows script…
Hello, thanks for moving my post here,
I change the some code lines in the command file and I worked perfectly thanks!
But now, my bootloader is unlocked and I’m afraid to lock it, and then to brick it (is it even possible?). I ran the script:
flashing get_unlock_ability
And got the result:
(bootloader) get_unlock_ability: 0
OKAY [ 0.007s]
Finished. Total time: 0.008s
That means i can’t unlock my phone later on?
Is there a risk if I run ./fastboot flashing lock_critcal ???
Is it risky to have an unlocked phone?
Sorry I’m not very familiar with all of this… I now just want to keep the original FP OS in a secure way.
Regards
When get unlock ability is 0 I would def not lock the bootloader, as there is a quite high risk you will brick your phone.
I think opinions differ on how unsecure an unlocked bootloader is, I think its not very risky, maybe search the forum, this was discussed before.
E.g here