There is no known way to get rid of permanent write protection (so yeah, there's no way to fix it). I also have a box in the same state (which actually uses Samsung eMMC too) and we already tried a lot of things (we even tried using Samsung backdoor cmds) with no luck.
If you ever manage to dump the ext_csd, you can check the eMMC status with this tool. If the eMMC went into read-only mode, it'll show you the following output:
Permanent write protection,PERM_WRITE_PROTECT,1,R/W,[13:13],0x1 Temporary write protection,TMP_WRITE_PROTECT,1,R/W/E,[12:12],0x0