An /E/asy Installer! will only start a successful installation if it installs at least one /e/ OS 8-Oero or better /e/ OS 9-Pie build for your Samsung Galaxy A5 (2017) SM-A520F.
The bootloader of StockROM Android 8.0.0 and /e/ OS e-0.7-n (7-nougat) usually do not fit together; this may mean that the device becomes unusable.
Starting with StockRom firmware Android 8.0.0 Oero version: FTM - France A520FXXU5CRGB - A520FFTM5CRG2 - A520FXXU*5CRF8 a new bootloader (v5 or higher) is used.
Firmware Android 8.0.0 Oero Version: FTM - France A520FXXU4CRF1 - A520FFTM4CRF1- A520FXXU4CREH still uses a bootloader (v4), just like Firmware Android 7.0 Nougat Version: FTM - France A520FXXU4BRC4 - A520FFTM4BRC2 - 520FXXU4BRC1 uses a bootloader (v4). The MODEM/CP version also changes. From this follows: Solution