SPIFFS won't initialise when booting from second rBoot slot

[mikee47]

For example, setting up a SPIFFS volume of 2MByte works fine when booting from slot #0 at 0x2000, but switching to slot #1 at 0x202000 fails to iniitalise.

Can result in spiffs_get_storage_config() reporting the requested SPIFFS size is too big.

The problem is with flashmem_get_info() which assumes that memory location 0x4020000 is the start of flash. However, rBoot remaps this address so it falls over. Instead, it should call flashmem_read at location 0. The sector at offset 0x200000 never gets properly initialised so returned data will be unpredictable.