ubi_io_read_ec_hdr(9)

🎀 ubi_io_read_ec_hdr(9) 🎀

okay bestie, so this one's a page from the Kernel API Manual and it's literally all about reading an erase counter header off your flash and vibe-checking it. let's get into it ✨

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🌸 NAME 🌸

ubi_io_read_ec_hdr — read and check an erase counter header. that's the whole gig, no cap 💅

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✨ SYNOPSIS ✨

int ubi_io_read_ec_hdr (struct ubi_device *ubi , int pnum , struct
ubi_ec_hdr *ec_hdr , int verbose );

like, four things in, an int out. icon behavior fr 🫶

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🦋 ARGUMENTS 🦋

• ubi — the UBI device description object. it's giving "the whole entire device", yk?
• pnum — the physical eraseblock you wanna read from. that's your address, bestie 📍
• ec_hdr — a struct ubi_ec_hdr object where we're gonna stash the erase counter header we just read
• verbose — turn this on and it will be verbose if the header is corrupted or straight-up wasn't found. loud and proud 🗣️

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💖 DESCRIPTION 💖

so what this function does is: it reads the erase counter header from physical eraseblock pnum, and stores it in ec_hdr. then — and this is the main character moment — it also checks the CRC checksum of the erase counter header it just read. 🔥

here are all the codes it might hand back to you, no omissions, periodt:

• 0 — the CRC checksum is correct and the header was successfully read. slay, we love a clean read 🌈
• UBI_IO_BITFLIPS — the CRC is correct, but bit-flips were detected and corrected by the flash driver. ngl this is harmless, but it may indicate that this eraseblock may become bad soon (but may be not 🙈). it's giving "watch this one, don't panic yet".
• UBI_IO_BAD_HDR — the erase counter header is corrupted, i.e. there's a CRC error. 💀
• UBI_IO_BAD_HDR_EBADMSG — same as UBI_IO_BAD_HDR, but there also was a data integrity error (uncorrectable ECC error in case of NAND). so it's bad and extra bad 😭
• UBI_IO_FF — only 0xFF bytes were read, so the PEB is supposedly empty. nothing to see here, literally 💀
• a negative error code — in case of failure. generic "it did not go", iykyk

⚠️ bestie pls read the codes, don't just check for < 0, because some of these are lowkey important signals about your flash's whole situation 🫶

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⭐ SEE ALSO ⭐

kernel file ./drivers/mtd/ubi/io.c, and literally the whole friend group:

ubi_io_read(9), ubi_io_write(9), do_sync_erase(9), torture_peb(9), nor_erase_prepare(9), ubi_io_sync_erase(9), ubi_io_is_bad(9), ubi_io_mark_bad(9), validate_ec_hdr(9), ubi_io_write_ec_hdr(9), validate_vid_hdr(9), ubi_io_read_vid_hdr(9), ubi_io_write_vid_hdr(9), self_check_not_bad(9), self_check_ec_hdr(9), self_check_peb_ec_hdr(9), self_check_vid_hdr(9), self_check_peb_vid_hdr(9), self_check_write(9), ubi_self_check_all_ff(9)

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and that's the page!! 🧚💜

kisses from ./drivers/mtd/ubi, dated October 2026 — go read some erase counter headers, bestie, you got this 💅✨🎀