Hello,
I managed to overcome the issue by talking on SeeedStudio’s forums. What I did is : reflash a new image with SDK manager on ubuntu 18.04, then I followed a tutorial to allow the sd card reader (downloaded a github), and finally followed another one to boot on the sd card instead of the integrated eMMMC.
Here are the different links :
reComputer J1010 | J101 | Seeed Studio Wiki
J101 Enable SD Card | Seeed Studio Wiki
J1010 Boot From SD Card | Seeed Studio Wiki
Best regards,
nono_o