Rockbox

Original code had the DMA controller writing two extra lines. When data was transferred to the GRAM on the LCD controller it wrapped around with the extra two lines of data (from outside of the allocated framebuffer). Hence the top two lines were garbled.

However, just changing the 0xde (222) to 0xdc (220) didn't entirely fix the problem. The top two lines were now blank instead of randomly changing. By offseting at least two lines lower

lcd_write_reg(R_RAM_ADDR_SET, (y << 2)+175) where y >= 2

the problem goes away. But then everything is offset by y lines.

So I worked around by filling in the GRAM from the bottom up.

lcd_write_reg(R_ENTRY_MODE, 0x6000);
lcd_write_reg(R_RAM_ADDR_SET, (219 << 2)+175)

The image was now flipped. So I flipped it back by changing R_DRV_OUTPUT_CONTROL_NORMAL.

It's a workaround, but without knowing exactly that all the LCD_REG_? do (no docs), it the best that I can do.

To use this patch, you must build a bootloader and install it as well (sansapatch -a new_bootloader).

It also clears up the garbled lines when you load the original firmware. To my knowledge, it should work on older e200s, but it has not been tested.