Align uf2 blocks to flash erase pages #763

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timokroeger wants to merge 1 commit from uf2-gaps into develop

timokroeger commented

2022-03-22 10:27:07 -05:00

(Migrated from github.com)

Fixes #762

The rp2040 bootrom uses the uf2 block number to determine when to erase a flash sector:
github.com/raspberrypi/pico-bootrom@c09c7f0855/bootrom/virtual_disk.c (L205)

When there is a gap in target addresses between two uf2 blocks this logic does not work out.
As a workaround align all uf2 blocks to page erase boundary, so that the bootrom always removes the correct sector.

Fixes #762 The rp2040 bootrom uses the uf2 block number to determine when to erase a flash sector: https://github.com/raspberrypi/pico-bootrom/blob/c09c7f08550e8a36fc38dc74f8873b9576de99eb/bootrom/virtual_disk.c#L205 When there is a gap in target addresses between two uf2 blocks this logic does not work out. As a workaround align all uf2 blocks to page erase boundary, so that the bootrom always removes the correct sector.

kilograham commented

2022-03-22 14:37:03 -05:00

(Migrated from github.com)

Argh; good catch on the bootrom bug.

Two things:

The changes should be limited to flash UF2 generation
I'm not sure the fix is quite right, because the block_num needs to change whenever the flash sector number does, and this is relative to the start of flash not the previous UF2 block address. I think a simpler, and the easier one conceptually, would be just to include zeroed data for any unused pages in a sector (they are going to be erased anyway).

Argh; good catch on the bootrom bug. Two things: 1) The changes should be limited to flash UF2 generation 2) I'm not sure the fix is quite right, because the block_num needs to change whenever the flash sector number does, and this is relative to the start of flash not the previous UF2 block address. I think a simpler, and the easier one conceptually, would be just to include zeroed data for any unused pages in a sector (they are going to be erased anyway).

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Align uf2 blocks to flash erase pages #763

Pull request closed