I've also already suspected the remapping of the address, but the working nand driver for CS0 does the same, it's base address is 0x08000000 and gets remapped into a similar memory region as mine.
As an info, the CS0 config:
GPMC_CONFIG1: 0x00000800
GPMC_CONFIG2: 0x00030300
GPMC_CONFIG3: 0x00030300
GPMC_CONFIG4: 0x02000311
GPMC_CONFIG5: 0x00030303
GPMC_CONFIG6: 0x03000540
GPMC_CONFIG7: 0x00000F48
best regards
Reinhard
