A Disk-On-Module (DOM) is a NAND flash memory-based device with legacy I/O interface which does not require any special device driver due to the presence of flash translation layer (FTL). FTL is an intermediate software layer which makes DOMs look like conventional hard disk drives. Since DOMs are usually used in mass-market consumer electronics devices, they are extremely cost-sensitive; hence FTL should be able to run in a severely resource-constrained environment. In this paper, we propose TinyFTL, a new FTL which employs an efficient memory management scheme for DOMs with a very small amount of memory. TinyFTL divides the mapping information into multiple levels and caches only recently-accessed mapping information in memory. According to experimental evaluation, TinyFTL shows the performance comparable to or better than the existing FTLs with only 4.3-6.2% of memory requirement (12KB) for 16 GB NAND flash memory.