Stock ROM is typically used for Android device system updates so that the shortcomings in the current version will be covered by the latest version.
Stock ROM in this post is installed via Recovery on Acer Android devices. By placing the Stock ROM file in SDCard memory, then you can direct it to the Stock ROM file.
Or if there is a serious problem on your Acer Android device such as Bootloop, Brick, Stuck on Logo or other system problems, then you can use Flashing Firmware which you can get on post "Download Acer Android Firmware (All Models)" and you also can get the Custom Recovery file (CWM / TWRP) and Stock ROM for Acer files of all models there. And maybe you also need Android USB Driver for Acer Android device, you can also get it on post "Download Acer Android USB Driver (All Models)".
|Stock ROM for Recovery Acer Liquid Z520|
|Name and Links||Size|
|Firmware - update_Acer_AV0K0_Z520_1.002.00_EMEA_MTSS-sds.zip||812 MB|
|Firmware - update_Acer_AV0K0_Z520_1.002.00_EMEA_GEN2-sds.zip||812 MB|
|Firmware - update_Acer_AV0K0_Z520_1.010.00_EMEA_GEN1S-sds.zip||876 MB|
|Firmware - update_Acer_AV0K0_Z520_1.010.00_EMEA_GEN1-sds.zip||876 MB|
|Firmware - update_Acer_AV0K0_Z520_1.003.00_EMEA_CUS1S-sds.zip||812 MB|
|Firmware - update_Acer_AV0K0_Z520_1.003.00_EMEA_CUS1.zip||813 MB|
|Firmware - update_Acer_AV0K0_Z520_0.004.00_AAP_GEN1.zip||719 MB|