--- /tmp/mtdpart.c  2020-09-18 12:19:25.221229865 +0200
+++ build_dir/target-x86_64_musl/linux-x86_64/linux-5.4.65/drivers/mtd/mtdpart.c    2020-09-18 12:20:35.982040806 +0200
@@ -260,7 +260,6 @@
    ret = part->parent->_erase(part->parent, instr);
    if (instr->fail_addr != MTD_FAIL_ADDR_UNKNOWN)
        instr->fail_addr -= part->offset;
-   instr->addr -= part->offset;

    if (mtd->flags & MTD_ERASE_PARTIAL) {
        if (partial_start) {
@@ -280,6 +279,8 @@
        kfree(erase_buf);
    }

+   instr->addr -= part->offset;
+
    return ret;
 }