The 20220126 iodeÓS v2.3 build? This is a very old build! In general when you re-lock a bootloader if the version of the current software is older than the prior system, then rollback protection is triggered and it will not boot. So you just need the updated iodéOS build.
Please see the manual install instructions here: ota / ota · GitLab with a link to the builds which should have you find the v7.2 version.
As a note, please make sure you start with NOT the newest FairphoneOS 16 February 2026 build. This will have security patches “one month newer” than the iodéOS builds (as our builds are based on LineageOS which takes a month to incorporate the upstream patches), or else it will again trigger rollback protection.
Also, please make sure that “Allow OEM Unlocking” is enabled before flashing iodéOS. Then if you do trigger rollback protection (or have any other flashing problem causing a “no boot” situation) you can always safely re-unlock the device and try again. But if you don’t “Allow OEM Unlocking” and you lock the bootloader upon install, and the install fails to boot for some reason, you will have a hard brick requiring Fairphone to reset the device.
Good Luck!