NES SNES V.B. N64 G.C. Wii said:
Format the micro SD card with Panasonic SD formatter, and install wood if it's from r4ids.com, otherwise install retrogamefan's YSMenu updates for R4 clones.
r4ids.com is the AKAIO 1.8.6a compatible one. The one supported by wood r4 is from
r4ids.cn. Just wanted to get that straight.
On Topic: maybe it's a corrupt or slow micro SD card; as mentioned before, format using the
panasonic SD formatter (note that formatting will erase everything in the micro SD card, so back-up any vital content in the micro SD card). Redownload the kernel for your cart and put it in.