Yes, this method also worked for me, however - the iodé recovery v4.10 was not updated to version 4.14.
With the installation of iode-4.14-20240724-cepheus-fastboot.zip and iode-4.14-20240724-cepheus-ota.zip, I received the same error message each time:
A “Factory data reset” does not force a better output length, but leads to the identical error again.
This error is systematic, because it also occurs with other iodéOS devices and also with other CustomROM Android distributions, for example with /e/OS and LineageOS 21.0 for microG and finally also with LineageOS 21.0.
The LineageOS Android distribution is the source code producer. This provides the basis for soft forks such as /e/ and iodéOS and LineageOS-for-microG. The cause of the incorrect installations is the recovery. The blind trust in the LineageOS source code and untested iodéOS updates then leads to a frustrating iodéOS user experience.
For the successful installation of iodéOS v4.14 for the Xiaomi Mi 9, I used the recoveries TWRP-cepheus-A14* and OrangeFox-cepheus-A14* recommended by crDroid Android Project. The installations went through without a hitch.