Cisco Catalyst 4000 Series Switches

Field Notice: WS-C4912G Hangs on Boot or Reports the Boot Image Is Damaged

Revised August 22, 2002

August 15, 2002

Products Affected




The units produced from January 2000 through July 2000 could be affected. See S/N list below.


Serial Numbers

Sequential #

Random #


FOX03531140, FOX03531141, FOX03531142, FOX03531143, FOX03531148, FOX03531151, FOX03531152, FOX03531154, FOX03531156, FOX03531158, FOX03531160, FOX03531162, FOX03531163, FOX03531164, FOX03531165, FOX03531167, FOX03531169, FOX03531170, FOX03531172, FOX03531173, FOX03531174, FOX03531175, FOX03531178, FOX03531179, FOX03531180, FOX03531181, FOX03531183, FOX03531184, FOX03531188, FOX03531191, FOX03531205, FOX03531207, FOX03531209, FOX03531213, FOX03531221, FOX03531226, FOX03531228, FOX04020716, FOX04020728, FOX04020729, FOX04020730, FOX04020734, FOX04020737, FOX04020739, FOX04020741, FOX04020742, FOX04020746, FOX04020747, FOX04020748, FOX04020749, FOX04020750, FOX04020754, FOX04020755, FOX04020757, FOX04020759, FOX04020767, FOX04020768, FOX04020769, FOX04020781, FOX04020790, FOX04020801, FOX04020802, FOX04020807, FOX04051348, FOX04051611, FOX04080315, FOX04080377, FOX04080378, FOX04080379, FOX04080380, FOX04080381, FOX04080382, FOX04080383, FOX04080387, FOX04080388, FOX04080389, FOX04080390, FOX04080391, FOX04080392, FOX04080393, FOX04080394, FOX04080395, FOX04080396, FOX04080397, FOX04080398, FOX04080399, FOX04080400, FOX04080401, FOX04080402, FOX04080403, FOX04080404, FOX04080405, FOX04080407, FOX04080408, FOX04080409, FOX04080410, FOX04080412, FOX04080413, FOX04080414, FOX04080416, FOX04080418, FOX04080419, FOX04080425, FOX04080427, FOX04080428, FOX04080429, FOX04080431, FOX04080434, FOX04080435, FOX04080451, FOX04080452, FOX04080453, FOX04080454, FOX04080457, FOX04080457, FOX04080458, FOX04080459, FOX04080460, FOX04080462, FOX04080463, FOX04080464, FOX04080469, FOX04080470, FOX04080471, FOX04080472, FOX04080473, FOX04080474, FOX04080475, FOX04082316, FOX04082317, FOX04082318, FOX04082320, FOX04082321, FOX04082322, FOX04082323, FOX04082324, FOX04082325, FOX04082326, FOX04082327, FOX04082328, FOX04082329, FOX04082330, FOX04082331, FOX04082332, FOX04082334, FOX04082335, FOX04082336, FOX04082337, FOX04082338, FOX04082339, FOX04082340, FOX04082341, FOX04082342, FOX04082344, FOX04082346, FOX04082347, FOX04082348, FOX04082350, FOX04082351, FOX04082352, FOX04082353, FOX04082354, FOX04082355, FOX04082356, FOX04082357, FOX04082358, FOX04082359, FOX04082360, FOX04082364, FOX04082366, FOX04082367, FOX04082369, FOX04082371, FOX04082372, FOX04082373, FOX04082374, FOX04082375, FOX04082376, FOX04082378, FOX04082379, FOX04082380, FOX04082384, FOX04082385, FOX04090017, FOX04090036, FOX04090051, FOX04130001, FOX04130003, FOX04130004, FOX04130006, FOX04130007, FOX04130008, FOX04130010, FOX04130011, FOX04130012, FOX04130013, FOX04130015, FOX04130016, FOX04130017, FOX04130019, FOX04130020, FOX04130021, FOX04130022, FOX04130023, FOX04130024, FOX04130026, FOX04130027, FOX04130028, FOX04130029, FOX04130030, FOX04130031, FOX04130032, FOX04130034, FOX04130037, FOX04130039, FOX04130040, FOX04130041, FOX04130041, FOX04130042, FOX04130043, FOX04130044, FOX04130045, FOX04130046, FOX04130047, FOX04130048, FOX04130049, FOX04130050, FOX04130051, FOX04130052, FOX04130053, FOX04130054, FOX04130055, FOX04130056, FOX04130057, FOX04130058, FOX04130059, FOX04130062, FOX04130064, FOX04130069, FOX04130073, FOX04130074, FOX04130079, FOX04130081, FOX04130083, FOX04130084, FOX04130085, FOX04130085, FOX04130086, FOX04130087, FOX04130087, FOX04130088, FOX04130089, FOX04130090, FOX04130091, FOX04130092, FOX04130093, FOX04130094, FOX04130095, FOX04130097, FOX04130098, FOX04130099, FOX04130100, FOX04130101, FOX04130102, FOX04130103, FOX04130104, FOX04130105, FOX04130106, FOX04130107, FOX04130108, FOX04130109, FOX04130110, FOX04130111, FOX04130112, FOX04130113, FOX04130115, FOX04130116, FOX04130118, FOX04130119, FOX04130120, FOX04130121, FOX04130124, FOX04130125, FOX04130128, FOX04130131, FOX04130132, FOX04130133, FOX04130134, FOX04130135, FOX04130136, FOX04130137, FOX04130138, FOX04130139, FOX04130140, FOX04130141, FOX04130142, FOX04130143, FOX04130144, FOX04130145, FOX04130146, FOX04130148, FOX04130149, FOX04130150, FOX04130151, FOX04130152, FOX04130153, FOX04130917, FOX04130918, FOX04130919, FOX04130920, FOX04130923, FOX04130925, FOX04130926, FOX04130927, FOX04130928, FOX04130929, FOX04130931, FOX04130932, FOX04130933, FOX04130934, FOX04130935, FOX04130936, FOX04130937, FOX04130939, FOX04130940, FOX04130943, FOX04130945, FOX04130946, FOX04130947, FOX04130948, FOX04130949, FOX04130950, FOX04130951, FOX04130952, FOX04130954, FOX04130955, FOX04130956, FOX04130957, FOX04130958, FOX04130959, FOX04130960, FOX04130961, FOX04130962, FOX04130963, FOX04130965, FOX04130966, FOX04130967, FOX04130968, FOX04130969, FOX04130970, FOX04130971, FOX04141016, TAB03160936, TAB03160950, TAB03210146, TAB03210147, TAB03210148, TAB03210149, TAB03210150, TAB03210155, TAB03210156, TAB03210157, TAB03210158, TAB03210159, TAB03210160, TAB03210161, TAB03210162, TAB03210164, TAB03210165, TAB03210167, TAB03210168, TAB03210169, TAB03210192, TAB03210205, TAB03210206, TAB03210208, TAB03210209, TAB03210210, TAB03210211, TAB03210214, TAB03210215, TAB03210217, TAB03210218, TAB03320904, TAB03320970, TAB03320973, TAB03320978,


Problem Description

The Catalyst WS-C4912G switches which have run a 5.4(1) or higher ROMMON and then been downgraded to a pre-5.4(1) ROMMON will fail to boot any online software images of 5.4(1) or later, due to an invalid ROMMON NVRAM parameter configuration. See S/N list for units that could be affected.


Any 4912G switch ordered from January 2000 to August 2000 and originally shipped with an image previous to 5.4(1) could suffer from this problem. The system might try to boot an image and immediately hang, or it might report that the image has been damaged, when in fact, the image stored in Flash is identical to that on CCO.

This problem arises because, starting with 5.4(1), the ROM communicates boot-time parameters to the online software via environmental variables stored in NVRAM. Unfortunately, if the ROMMON is downgraded below 5.4(1), those parameters are not deleted, but are now incorrect, and the online software cannot find all of the information that it needs to boot. Manufacturing was producing WS-C4912G switches, which were originally programmed with the 5.4(1) ROM and then (incorrectly) "upgraded" to 4.5(1) before being shipped. Those that were ordered with 5.4(1) or later online software were detected by the final test, and the errant variables were removed.

Problem Symptoms

The system might try to boot an image and immediately hang, or it might report that the image has been damaged, when in fact the image stored in Flash is identical to that on CCO.

Basically, the problem here is that any Catalyst 4000-family switch which has run a 5.4(1) or later ROMMON and then been downgraded to a pre-5.4(1) ROMMON will fail to boot any online software images of 5.4(1) or later, due to an invalid ROMMON NVRAM parameter configuration.


There are three potential fixes:

  1. Boot to the ROMMON prompt and manually unset five environment variables.

  2. Upgrade to newer online software images which will detect and correct the problem. 5.5(4) will fix it, as should 6.1(2) and 6.2(1), when they are released. 6.1(1) will not fix it.

  3. Upgrade to a newer ROMMON which will detect and correct the problem. The ROMMON to use is 5.5(4).

Of the three, the last (upgrading to ROM 5.5(4)) is the most desirable, because it results in a switch running the latest ROMMON, with several important bug fixes incorporated. All of these images are available on CCO at Cisco Catalyst 4000 Software Images (registered customers only)

Further technical info:

It is desirable for a customer to be running a 5.4(1) or later ROMMON for several reasons. ROMs previous to this cannot boot images larger than about 4MB, and while no customer-shipped images are this large yet, they may be in the future. Also, 5.4(1) fixes a serious bug (CSCdm80016) in which frequently power cycling a switch could break the autoboot state machine, resulting in the switch dropping to the ROMMON prompt and requiring manual intervention to get it to boot again. See Field Notice: Successive Power Cycling During a Boot Leaves the Switch in ROMMON for more information on this problem

For More Information

If you require further assistance, or if you have any further questions regarding this field notice, please contact the Cisco Systems Technical Assistance Center (TAC) by one of the following methods:

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