ENV Q&A

Q1：Does ENV support backup partitions?

Y.

Q2：What is the ENV backup mechanism?

  1. The ENV of nand flash has two partitions, ENV and ENV1, which occupies two blocks (2*128K) respectively. The actual data length is 4K. The partition supports skipping a bad block.

  2. Nor flash will not have bad blocks, so it has only one ENV partition. The size of UBOOT_ENV partition is 2*4K. Each 4K in the partition is a complete ENV data, which is a backup for each other.

Q3: Is the data of the two backup partitions of ENV exactly the same?

Except that the first burn is completely consistent, each saveenv is alternated, so there will be a saveenv difference between the two ENVs. If you want to keep the same, do saveenv twice after setenv.

Q4: After the kernel is running, is it supported to set ENV variables in user mode?

Y, the setting can be completed through the bin of fw_printenv provided by uboot util.

Q5：Does setting ENV through fw_printenv support env backup mechanism?

Y.