How I Migrated U-Boot to Support a New eMMC Chip After Samsung’s Line Shutdown
When Samsung announced the discontinuation of one of its widely used eMMC product lines, many embedded vendors were forced to make quick adjustments. In our case, the eMMC used on one of our Rockchip-based boards became EOL (End of Life), and we had to quickly replace it with a different vendor's part to keep production moving. This article documents the steps I took to modify U-Boot to support the new eMMC chip, including datasheet analysis, pin compatibility checks, register tuning, and extensive code changes. Background Our board is based on a Rockchip SoC (RK3566), using a Samsung eMMC for storage. The original chip had been in stable production until Samsung shut down its eMMC production line for that model. The replacement chip came from a different vendor, with different electrical specs and initialization behavior. The challenge was that the replacement chip: Had different timing requirements (especially HS400 mode). Required tuning of EXT_CSD registers. Had a slightly diff...