Originally Posted by Luescoff
Now my tablet boots with a white text on it saying custom bootloader. But i don't have recovery mode.
Install new recovery with fastboot. Boot into Android normally and connect it to PC with Android SDK (you need working adb and fastboot commands).
Check if adb sees your device:
Boot into bootloader:
adb reboot bootloader
If you haven't been in bootloader mode before you might need to install fastboot drivers (from ACER Drivers for example).
Check if fastboot sees your device:
My a500 didn't return its ID so fastboot is showing a device with "?" instead of ID. It is ok.
Install new recovery (here it is in recovery.img file, change it to yours):
fastboot erase recovery
fastboot flash recovery recovery.img
When device will be booting just hold Volume Down like always to get into recovery.
You can also test and boot recovery.img directly from PC with fastboot:
fastboot boot recovery.img
You can test with fastboot boot command as it doesn't overwrite anything in device's flash. It downloads boot image (like recovery.img or boot.img into RAM and runs it from there).