check it maybe will help, good luck !
I bought my Acer A1-810 it’s 2,5 months (from amazon). And few days ago I decided to root it. 1 hour later i realized that was not a really good idea, because i did not know much things about, and it was not as easy as I thought. and voila as a result : bootloop !
I tried different roms, different update.zips but got allways the same error : ” check.partition.size=[__PROP_UNDEFINED__] ”
I was desperate…I was at the point of resend it to Acer for repair. But last try was successful, I did it, I did !!! And there is how !
1. go to acer web page --->support--->drivers and manuels
2. choose your model acer a1-810
3. As my divece was bought in usa, my FW upgrade is AV052.RV26RC06.PA.CUS1 (in O.S ), download it !
4.when it’s done, you should unzip and should get update.zip separately.
5. Put update.zip on SD card
6.Put SD card in your device.
For next steps see the manuel of update